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Transcriber's Note:

Italic text is denoted by _underscores_ and bold text by =equal signs=.
All corrections in the ERRATA section below have been made in the text.





THE ORNITHOSAURIA:


AN ELEMENTARY STUDY


OF


THE BONES OF PTERODACTYLES.


Cambridge:

PRINTED BY G. J. CLAY, M.A. AT THE UNIVERSITY PRESS.




THE ORNITHOSAURIA:


AN ELEMENTARY STUDY


OF


THE BONES OF PTERODACTYLES,


_MADE FROM FOSSIL REMAINS FOUND IN THE
CAMBRIDGE UPPER GREENSAND,_

AND

ARRANGED IN THE WOODWARDIAN MUSEUM OF THE
UNIVERSITY OF CAMBRIDGE


BY


HARRY GOVIER SEELEY,

OF ST. JOHN'S COLLEGE, CAMBRIDGE.


_WITH TWELVE PLATES._


"_And when the appointed end comes, they lie not dishonoured in
forgetfulness_,"--Xenoph. _Memor._ Book 2, c. 1, § 83.


[Illustration: Cambridge:]

DEIGHTON, BELL, AND CO.

LONDON: BELL AND DALDY.

1870.


[_All Rights reserved._]


_The expense of printing this volume has been defrayed out of the Funds
of the Syndics of the University Press; and Professor Sedgwick hereby
expresses his grateful thanks to them for this great favour._




PREFACE.


This memoir is a portion of the Catalogue of the Woodwardian Museum
which has been made at Professor Sedgwick's request and at his cost.
When the Professor laid upon me his commands to prepare a Catalogue of
the Museum, it was planned in three distinct works. First, a series of
indexes to the specimens in the great divisions into which the Museum
is arranged; secondly, a series of memoirs upon the orders and classes
of animals concerning which new knowledge is given by fossils in the
Museum; and, thirdly, memoirs descriptive of those species contained
in the arranged collections which are at present unknown in scientific
writings.

For the convenience of students the Catalogue is made in parts. The
Syndics of the University Press printed last autumn as an example of
the "Indexes to the Museum," an Index to the Pterodactyles, Birds,
and Reptiles from the Secondary Strata. And this memoir is an example
of the second kind of Catalogue, which explains the structures of the
Pterodactyles of the Cambridge Greensand. In its progress questions
have arisen which necessitated an examination both of the method, of
research in comparative anatomy and of its results in classification.
And in so far as the views here advanced differ from those commonly
taught, the discrepancy is due to the writer's imperfect faith in the
results of the inductive method of research, as commonly used by modern
writers on Palæontology. It has not been consistent with the plan of
this little work to do more than scatter through it a few hints upon
method, a subject which will more fitly be discussed with a part of the
Catalogue which forms a synopsis of the osteology of the fossil animals
usually named Reptiles. The views here urged have however but little
of novelty. The name Ornithosauria was proposed by the distinguished
naturalist Prince Charles Bonaparte in 1838. The group as an order was
recognized by Von Meyer in 1830. The affinities of the brain appear
to have been detected by Oken, and the bird-like character of the
respiratory system was expounded by Von Meyer. And most of whatever
this memoir contains has been already thought or discovered by the
German philosophers, who have had the Pterodactyles as fossils of their
fatherland, though my own conclusions were arrived at separately and
from different materials.

The oldest Ornithosaurians are from the Muschelkalk of Germany.
In England the oldest are from the Lias,--several species of
Dimorphodon--a genus in some respects nearly resembling the
Pterosaurians of the Cambridge Upper Greensand. In the Oolite of
Stonesfield are several species of Rhamphorhynchus or a similar genus.
The great Pælolithic period from the Oxford Clay to the Kimeridge
Clay, has yielded in its several divisions small Pterodactyles of
new species. And the Psammolithic period from the Portland Sand to
the Lower Greensand has afforded many excellent remains both of true
Pterosaurians in the Purbeck, Wealden, and Potton Sands, and of animals
which indicate a new order of Ornithosauria having affinities with
Von Meyer's thick footed saurians, the Dinosauria. In the Cretaceous
series, Galt, Upper Greensand, and Chalk all have representatives
of the Pterosauria; but no English stratum has hitherto yielded
so many as the Cambridge Upper Greensand. From this formation the
collection accumulated during Prof. Sedgwick's long professoriate is
unequalled; though, excepting a few fine bones from the Chalk and
the Purbeck Limestone, the Woodwardian Museum is as yet deficient in
Ornithosaurians from the other Secondary Rocks. Until descriptions
of these animals shall have been published a classification of the
Ornithosauria must necessarily be provisional. And it cannot be
expected that descriptions of the structure of Cretaceous Pterosaurians
here given will hold good for all the Ornithosaurian sub-class.

Finally, I have gratefully to express my thanks to the many friends,
English and German, who have aided me with specimens and with their
writings; to the chiefs and officers of the English museums, especially
Prof. Owen, Prof Humphry, Prof Newton, Prof Phillips, Prof Flower, and
Prof. Huxley; to the officers of the University Library, especially
Mr Bradshaw, and Mr Crotch, for aid in consulting books; but chiefly
to Prof Sedgwick, who while employing me as his paid Assistant to
aid him in his Museum work, has generously encouraged me to carry on
for several years, without restraint and as part of my daily labour,
an investigation of which this treatise is the first fruit. Prof.
Sedgwick has placed at my disposal an ample number of copies for
distribution among those who take an interest in the Museum; and
especially among those who have contributed to the Ornithosaurian
collections, and aided me in my work.

  _January 3, 1870._




CONTENTS.


                                         _Page_
  Introduction                                1
    Materials                                 1
    History                                   3
    Organization                              7
      Cuvier                                  7
      Sömmerring                             10
      Oken                                   10
      Wagler                                 11
      Goldfuss                               11
      Wagner                                 14
      Quenstedt                              17
      Burmeister                             17
      Von Meyer                              17
    Another view of the Ornithosauria        24

                  --------------

  Osteological collection illustrative of modifications of Ornithosauria in
    the Cambridge Greensand, pp. 28-94.

    Sternum                                  28
    Coracoid                                 32
    Scapula                                  35
    Humerus                                  38
    Radius and Ulna                          42
    Proximal carpal                          48
    Distal carpal                            50
    Lateral carpal                           51
    Metacarpal bone of wing-finger           53
    First phalange of wing-finger            56
    Second phalange of wing-finger           57
    Claw phalange                            59
    Os innominatum                           59
    Femur                                    62
    Tibia                                    62
    Tarso-metatarsus                         63
    Atlas and axis                           64
    Cervical vertebræ                        65
    Dorsal vertebræ                          69
    Sacrum                                   73
    Caudal vertebræ                          75
    Bones of the head                        77
    Basi-oocipital bone                      78
    Back of the cranium                      80
    Back of another cranium                  84
    Ethmo-sphenoid                           85
    Mould of the brain-cavity                87
    ?Vomer                                   88
    Quadrate bone                            89
    ?Pterygoid end of palatine bone          91
    Premaxillary bones                       91
    Lower jaw                                91
    Teeth                                    92

                  --------------


  Conclusion                                 94
    A summing up                             94
    Restoration                             103
    Speculations on habits and aspect       104
    Notes on German specimens               106
    Classification                          108
    Synopsis of species                     112

                  --------------


  Appendix                                  129
  Index                                     133
  Plates, and explanation of Plates.




ERRATA.


  PAGE LINE

   4,    2, from bottom, _for_ procælian _read_ procœlian.

   7,   13, _for_ Ossements _read_ Ossemens.

   8,       last line, paragraph (2), _for_ outermost _read_ innermost.

  10,   21, }
  11,    5, } _for_ Sömmering _read_ Sömmerring.
  11,   13, }

  14,       note, _for_ Beyerischen _read_ Bayerischen.

  15,    5, _for_ ?zygapophyses _read_ spinous-processes.

  17,    6, from bottom, _for_ Herman _read_ Hermann.

  37,    5, from bottom, _after_ "spine as" _insert_ "are"

  92,       line above 'the Dentary Bone,' _for_ Pterodactyle _read_
            Pterodactyles.

  97,   11, _for_ Günter _read_ Günther.

  99,    4, _for_ Ichthyopteria _read_ Ichthyopterygia.

  101,  11, from bottom, _for_ procælous _read_ procœlous.

  102,  15, _for_ procælous _read_ procœlous.

  111,   8, _for_ Sömmering _read_ Sömmerring.

_For_ epipubic bone _read_ prepubic bone, pp. 61, 102, 109, 110, 111,
and pl. 8.





                             INTRODUCTION


                                TO THE


                OSTEOLOGY OF THE ORNITHOSAURIA FROM THE
                      CAMBRIDGE UPPER GREENSAND.

                          --------------


                              Materials.



The Cambridge Upper Greensand has yielded to collectors bones which
illustrate nearly every part of the skeleton of the animals that are
commonly named Pterodactyles. Large collections have been acquired
for the Woodwardian Museum. A series of more than 500 bones have
been arranged to exemplify the osteology and organization of the
Ornithosauria in the area when the Cambridge Greensand was deposited.
And this memoir is written to explain briefly some of the structures
of the soft and hard parts of those animals which are exhibited or
demonstrated by these relics. Another collection of nearly 400 bones
has been arranged, which displays in association, as they were found
entombed in the old Greensand sea-bed, the remains of the skeletons of
thirty-three animals of the Pterodactyle kind. The whole of the remains
from this formation hitherto gathered cannot be computed to have
pertained to fewer than 150 individuals, which indicate a new sub-class
of animals, two new genera and at least twenty-five new species.

The bones were mostly of a paper or card-like thinness, and were
originally hollow like the thin bones of birds. In the jaws of other
animals, and in the sea, they were easily fractured, so that proximal
ends and distal ends and shafts and split bones abound, while perfect
bones are almost unknown. Even those bones like the carpals, which
almost retain their entirety, invariably show indications of having
been rolled on the sea-shore among the nodules of phosphate of lime
with which they now occur, in their angular margins being rounded, and
in the removal of slender processes. The rock in which these fossils
are found is a thin bed of chalky marl which is heavily charged with
dark-green grains of Glauconite, and is quarried largely, and entirely
dug away to be deprived of the dark-brown nodules of phosphate of lime
with which it is stored. In digging and in the subsequent washing, the
workmen, stimulated by an ample reward, pick out the fossils as they
are discovered. They are separated easily from the matrix of investing
marl, so that every aspect of each bone is seen, except for the
occasionally adherent oysters and the masses of phosphate of lime, with
which material the bones are also filled. Hence these remains afford
facilities for the study of the _joints_ such as no other specimens
have presented; and from their large size and comparatively great
numbers, render easy the labour of the student who seeks to contrast
them with the bones of other animals.

The osteological collection has been formed without regard to species
or genera, and arranged to exhibit the structure and organization of
the tribe of animals. So far as possible each bone, as humerus, femur,
&c., has its variations of structures and form contrasted on a single
tablet. The series comprises the following bones:

  Fore-part of sternum. Coracoid (perfect). Scapula (nearly perfect).
  Humerus (perfect). ?Radius (proximal end). Radius (distal end). ?Ulna
  (proximal end). Ulna (distal end). Proximal carpal. Distal carpal.
  Lateral carpal. Wing-metacarpal (proximal and distal ends). First
  phalange (proximal and distal ends). Second phalange (proximal end).
  Metacarpal or metatarsal (distal end). Claw phalange. Os innominatum
  (parts of ilium, ischium, and pubis). Femur (perfect). ?Tibia
  (proximal end). Atlas and axis. Cervical vertebræ. Dorsal vertebræ.
  Sacrum and sacral vertebræ. Caudal vertebræ. Lower jaw (dentary and
  articular ends). Premaxillary bones, &c. Teeth. Quadrate bone (distal
  end with quadrato-jugal). Ethmoid with basi-sphenoid. Occipital and
  parietal segments of skulls. Basi-occipital and basi-temporal. Cast
  of brain-cavity.

They are exhibited in Compartments _a_, _b_, _c_ of the Table-case of
Cabinet =J=. The letter =F= in a circle is placed against figured
specimens.



History.

The Cambridge Pterodactyles first attain prominence in scientific
literature in the year 1859. Professor Owen had figured (plate 32, fig.
6-8) fragments of bones in the Palæontographical Society's Monograph
for 1851; the distal end of a large ulna (fig. 6); the shaft of a
phalange of the wing-finger, probably the first (fig. 7); and the upper
portion of the shaft of a small humerus showing part of the radial
crest (fig. 8). Inadvertently the last specimen was referred to the
Lower Greensand. But although fragments of humerus of Pterodactyle and
vertebræ of Pterodactyloid animals have in the last few years been
gathered from the Potton Sands, those deposits were believed to be
barren of fossils when Prof. Owen wrote; and all the Pterodactyles yet
made known from near Cambridge were collected from the Cambridge Upper
Greensand.

Among the earliest successful collectors were Mr James Carter, the
Rev. H. G. Day, St John's Coll.; Prof. G. D. Liveing, St John's Coll.;
the Rev. T. G. Bonney, St John's Coll.; and Mr Lucas Barrett, Trin.
Coll.; and the Rev. Prof. Sedgwick, Trin. Coll., on behalf of the
Woodwardian Museum. Mr Day and Mr Bonney both presented every specimen
from their cabinets which could enrich the University collection. And
in the last ten years the Woodwardian Museum has acquired, through the
skillful collecting of the Messrs Farren, the present materials. The
associated sets of bones were formed by William and Robert Farren,
who, obtaining the specimens from day to day as they were discovered,
were enabled to put together such parts of the skeleton as remained
together on the sea-bottom. These collections will hereafter be used
for the elucidation of species. They are the only materials which can
give the proportions of the Cambridge Ornithosaurians, and the contrast
of aspect which distinguished the living animals from those from other
rocks.

The other collections of these fossils are those of Mr William Reed
and Mr J. F. Walker at York, the Museum of Practical Geology, and the
British Museum.

The Woodwardian specimens as collected were placed in the hands of
Prof. Owen, and were first made known in the Professor's lectures on
reptiles and birds delivered at the Museum of Practical Geology in
1858. In that year Prof. Owen communicated to the British Association
for the Advancement of Science, and printed in their Report, the matter
of the memoir which was published with plates by the Palæontographical
Society in 1859. In this latter year Prof. Owen communicated to the
Royal Society an account of the vertebral column of Pterodactyles. In
1859 Prof. Owen also produced a classification of recent and fossil
reptiles at the meeting of the British Association, in which the
order Pterosauria appears with new characters--such as the pneumatic
structure of most of the bones--drawn from Cambridge specimens. In
1860 Prof. Owen produced another memoir on Pterodactyles, which was
published by the Palæontographical Society. A brief account of the
tribe appeared about the same time in the Professor's _Palæontology_.

In these writings are descriptions of the various parts of the
vertebral column. Their procœlian centra are described, and the
pneumatic foramina are noticed and supposed to have communicated
with air-cells. They are compared with birds, and distinguished from
birds; but although the order is classed with reptiles no contrast with
reptiles is made. Other bones described are a basi-occipital, and a
doubtful bone, then thought to be a frontal, but which is more like the
neural region of the sacrum.

The sternum is compared with the sternum of the birds Apteryx and
Aptenodytes, is stated to be formed, in the main, on the Ornithic type,
and to possess distinct synovial articular cavities for the coracoids
such as only occur in birds. The inter-coracoid process of the sternum
is compared with that of Bats, Birds, and Crocodiles.

The mechanism of the framework of the wings is said to be much
more bird-like than bat-like, the anchylosed scapula and coracoid
being remarkably similar to those of a bird of flight. The coracoid
is shorter and straighter in birds than in Pterodactyles, but no
comparisons are made with reptiles.

The humerus is known only by the proximal end. It is said to conform
at its proximal end more with the Crocodilian than with the Avian
type, but to have the radial crest much more developed than in either
Crocodile or Bird. The bone is, however, chiefly compared with
birds, and is figured between corresponding bones of a Vulture and a
Crocodile. The pneumatic texture is said to be as well marked as in any
bird of flight.

Of the carpus it is said, the Pterodactyle, in the complete separation
of the metacarpus from the antibrachium by two successive carpals
answering to the two rows, adheres more closely to the reptilian type
than to that of birds. But the row which was regarded as proximal is
the distal row, while the supposed distal row is proximal.

The claw-phalange and distal end of the wing-metacarpal, the mandible,
teeth, and jaw are the other bones described, but their comparative
osteology is not discussed. In the Professor's account of a fragment of
a jaw it is said, "The evidence of the large and obviously pneumatic
vacuities now filled with matrix, and the demonstrable thin layer of
compact bone forming their outer wall, permit no reasonable doubt
as to the Pterosaurian nature of this fossil. All other parts of
the flying reptile being in proportion, it must have appeared with
outstretched pinions like the soaring Roc of Arabian romance, but with
the demoniacal features of the leathern wings with crooked claws, and
of the gaping mouth with threatening teeth, superinduced."

When the specimens on which Prof. Owen had founded the foregoing views
of the osteology and classification of these animals were at length
returned to the Woodwardian Museum, it became a duty of the present
writer to arrange and name them. And in a Memoir on Pterodactyles which
was communicated to the Cambridge Philosophical Society and read March
7 and May 2 and 16, 1864, a position was claimed for them, distinct
from reptiles, as a separate sub-class of Sauropsida, nearly related to
birds.

In September of the same year a communication was made to the British
Association "On the Pterodactyle as evidence of a new sub-class of
vertebrata (Sauromia)," with enlarged drawings of the skull and some
of the other bones, in which the conclusions arrived at were that,
excepting the teeth, there is little in such parts of the head as are
preserved to distinguish the Cambridge Pterodactyles from birds; and
that the remainder of the skeleton gives a general support to the
inference from the skull.

Papers were communicated to the Cambridge Philosophical Society
on February 17, 1868, on indications of Mammalian affinities in
Pterodactyles in the pelvis and femur, and February 22, 1869, on the
bird-like characters of the brain and metatarsus in the Pterodactyls
from the Cambridge Greensand. The other references to Cambridge
specimens are in a paper "On the literature of English Pterodactyles"
in the _Annals and Magazine of Natural History_ for Feb. 1865, and in
"An epitome of the evidence that Pterodactyles are not reptiles, but
a new sub-class of vertebrate animals allied to birds," in the same
magazine for May, 1866.

In the meantime Prof. Owen's views have somewhat changed. In the first
volume of the _Comparative Anatomy and Physiology of the Vertebrata_
(1866), the Pterosauria are classed as the highest group of reptiles,
and take rank above the Dinosauria. In the second volume of that work
(1866), occurs the following passage:

"Derivatively the class of birds is most closely connected with the
Pterosaurian order of cold-blooded air-breathers. In equivalency it is
comparable rather with such a group than with the Reptilia in totality,
or with the Mammalia."


Organization.

Nearly every writer on Pterodactyles, who has expressed any opinion
at all, has formed an estimate of his own of their organization. They
have been assigned to almost all possible positions in the vertebrate
province, by great anatomists who all had before them very similar
materials. An account of these views is given by von Meyer in his
monograph of the Pterodactyles of the Lithographic Slate. It will not
be necessary to discuss these conclusions here, for the materials
from the Lithographic Slate and those from the Cambridge Greensand
are so different that no light would be thrown on the organization of
the animals by an exposition of any fallacious inferences from German
specimens. In England they are classed with Reptilia, chiefly through
the influence of the discourse upon them given by Baron Cuvier in his
_Ossemens Fossiles_[A]. It therefore may conduce to a clear view of
the subject to quote in Cuvier's words the passages in that memoir
which have been supposed to establish their position among reptiles. He
says,--"Ayant encore porté mon attention sur le petit os cylindrique
marqué _g_ (i.e. os quadratum) qui va du crâne à l'articulation des
mâchoires, je me crus muni de tout ce qui étoit nécessaire pour classer
ostéologiquement notre animal parmi les reptiles." The exact relations
of the quadrate bone are not seen in either Cuvier's or Goldfuss' or
von Meyer's figures of this Pterodactyle, the P. longirostris; but in
von Meyer's figures of P. crassirostris, P. longicollum, and P. Kochi
it appears to be a free bone articulated to the squamosal and petrosal
region of the skull and with the lower jaw. This is not the case with
either Chelonians or Crocodiles, which have the quadrate bone firmly
packed in the skull; nor is it paralleled even among those lizards
and serpents which have the bone as free; while, on the contrary, it
is characteristic of the whole class of birds. The form of the bone
is not more Lacertian than Avian, while its direct attachment to the
bone of the brain-case finds no parallel among lizards, but is exactly
paralleled in all birds.

[Footnote A: Tome V. Part a, pp. 358, 383. Edition, 1814.]

Cuvier then goes on to say, "Ce n'étoit pas non plus un oiseau,
quoiqu'il eût été rapporté aux oiseaux palmipèdes par un grand
naturaliste[B]." Which position he supports as follows:--

[Footnote B: Blumenbach.]

(1) "Un oiseau auroit des côtes plus larges, et munies chacune d'une
apophyse récurrente[C]; son metatarse n'auroit formé qu'un seul os,
et n'auroit pas été composé d'autanut d'os qu'il a de doigts." These,
though they may not be characters which are those of birds, are
certainly not eminently reptilian. The elongated form of the tarsals
in birds is peculiar, but quite functional, as may be seen among the
Penguins, where, when the so-called tarso-metatarsal bone is no longer
erect, it becomes much shorter, and is nearly separated into three
distinct bones. The cretaceous Pterodactyles appear to have this bone
exactly like that of birds.

[Footnote C: This shown in other specimens since figured, and in the
specimen from Stonesfield in the Oxford Museum.]

(2) "Son aile n'auroit eu que trois divisions après l'avantbras, et non
pas cinq comme celle-ce." This is a difference, but a difference of
detail only, and not a reptilian character. The creatures have wings;
and no reptile known, from recent or fossil specimens, has wings. The
general plan of the wing, though very unlike, approximates to that of
a bird. Most birds have two phalanges in the long finger, though some
have three. One Pterodactyle is described as having only two phalanges
in the wing-finger, while most of the German specimens appear to have
four phalanges. In birds the longest finger appears to be the middle
one, while in Pterodactyles it is the innermost one.

(3) "Son bassin auroit eu une toute autre étendue et sa queue
osseuse un toute autre forme; elle seroit élargie, et non pas grêle
et conique." The pelvis of Pterodactyle is not reptilian, and no
living reptile has a pelvis like it. It is not unlike the pelvis of
a Monotreme, but the ilium is more Avian. It resembles the pelvis
of Dicynodon. And the discovery of a long-tailed bird-like the
Archæopteryx shows that the tail is like that of old birds, even if
it also presents some analogy in form to that of certain reptiles and
mammals.

(4) "Il n'y auroit pas eu de dents au bec; les dents des _harles_ ne
tiennent qu'à l'enveloppe cornée, et non à la charpente osseuse." This
is not a reptilian character. Among reptiles some tribes have teeth,
others want them; and among mammals some animals are without teeth,
though they are so characteristic of the class. It is an anomaly that
birds should all be toothless. And so, without citing the supposed
teeth of _Archæopteryx_, it may be affirmed that it would be no more
remarkable for some birds to have teeth than it is for some mammals and
reptiles to be without them.

(5) "Les vertèbres du cou auroient été plus nombreuses. Aucun
oiseau n'en a moins de neuf; les palmipèdes, en particulier, en ont
depuis douze jusqu'à vingt-trois, et l'on n'en voit ici que six ou
tout au plus sept." This is a variation of detail such as, had it
occurred among birds, would hardly have been deemed evidence of their
affinities. When the variation of the neck-vertebræ ranges from 23 to
9, the further reduction of the number to 7 becomes insignificant, and
does not show that the animal was a reptile.

(6) "Au contraire, les vertèbres du dos l'auroient été beau-coup moins.
Il semble qu'il y en ait plus de vingt, et les oiseaux en ont de sept
à dix, ou tout au plus onze." This modification is obviously the
result of smaller development of the pelvic bones from front to back,
and hence of the small number of vertebræ in the sacrum. It does not
support the reference of Pterodactyles to the class of reptiles.

Speaking of the teeth, it is said, "Elles sont toutes simples,
coniques, et à peu près semblables entre elles comme dans les
crocodiles, les monitors, et d'autres lézards." The teeth of
Pterodactyles are (in the skull) for the most part in the premaxillary
bones, in which it is so characteristic for the teeth of animals to, be
merely conical and simple. Therefore it would have been difficult to
imagine the teeth to have been anything but what they are, whatever the
affinities of the Pterodactyle might be.

It is remarked, "La longueur du cou est proportionée à celle de la
téte. On y voit cinq vertèbres grandes et prismatiques comme celles des
oiseaux à long cou, et une plus petite se montre à chaque extrémité."
This adds nothing to the evidence for its reptilian character.

"Ce qui est le plus fait pour étonner, c'est que cette longue téte
et ce long cou soient portés sur un si petit corps; les oiseaux
seuls offrent de semblable proportions, et sans doute c'est, avec la
longueur du grand doigt, ce qui avoit determiné quelques naturalistes
à rapporter notre animal à cette classe." Nor is this evidence that
the animal was a reptile. And in many minor matters Cuvier is careful
to show how their modifications resemble those of birds; and when
this is not so, birds are the only animals from which he finds them
varying. And the few suggestions which are thrown out respecting their
affinities with lizards are upon points which are also common to birds.

Thus what Cuvier did was to distinguish these animals from birds, and
incidentally to show that their organization was a modification of
that of the Avian class. And the legitimate inference would have been
that their systematic place was near the birds, and not that they were
reptiles.

But in Germany Cuvier's views on Pterodactyles have by no means been
submissively received; and great anatomists, since he wrote, have
propounded and defended views as various as those of the anatomists
who preceded him, and with no less confidence in the results of their
science. In the brief space at my command it would be impossible to
do justice to the works of this array of philosophers, and therefore
I present in a somewhat condensed version the epitome of their
conclusions given by Hermann von Meyer in his _Reptilien aus dem
Lithographischen Schiefer der Jura_. They form a commentary on the
casts of Solenhofen Pterodactyles contained in the Woodwardian Museum.


Sömmerring

regarded the Pterodactyle as an unknown kind of bat, and thought that
Cuvier was misled by Collini's imperfect description. He believed that
he found in them different kinds of teeth as in mammals; and regarded
them as differing from bats chiefly in having larger eye-holes, a
longer neck, four fingers and four toes, a longer metatarsus, and in
having but one elongated finger; and found the closest analogue of the
fingers in Pteropus marginatus of Bengal. And although inclined to
place the Pterodactyle between Pteropus and Galeopithecus, he suspects
from the bird-like characters of the head and feet that its true place
is intermediate between mammals and birds.


Oken[D].

[Footnote D: _Isis_, 1818, p. 551.]

Oken reasoned carefully so far as his materials went. He dwells much
on the analogy of the wing to that of a bat, and seems to suspect that
the marsupial bones would hereafter be found; and, excepting the head,
finds that the other parts of the skeleton have their corresponding
bones among mammals.

Afterwards, when he saw the specimens at Munich, he was so much struck
at finding the quadrate bone of Lacertian form, though Sömmerring
could not detect it even with a microscope, that he is shaken in his
mammalian faith, and inclines to consider the animal a reptile.


Wagler[E].

[Footnote E: _System der Amphibien_, 1830, p. 75.]

Wagler was impressed with the resemblance of the jaws and the rounded
back part of the skull to those of Dolphins, and so far as the head
went conceives it to have had nothing in common with Lizards. He
recognizes mammalian characters in the pelvis and sternum, and fails,
like Sömmerring, to detect a quadrate bone, and finds the sum of the
characters like those of other extinct animals, such as Ichthyosaurus
and Plesiosaurus, suggesting for it a position between mammals and
birds. He supposed it unable to fly, that it never left the water,
but swam about on the surface like a swan, and sought its food on
the sea-bottom. He imagined the long arms to have been used after
the fashion of turtles and penguins to row the body along; while to
the claws he attributes the function of holding the females in the
generative process.


Goldfuss[F].

[Footnote F: _Nova Acta Acad. Leopold._, 1831, Vol. XV. Pt. I. p. 103.]

sees in Pterodactyle an indication of the course that nature took in
changing the reptilian organization to that of birds and mammals. The
less important organs, those of motion, assimilate partly to those
of the bird and partly to those of the bats, but always preserve
the fundament reptile type and reptile number of bones. The skull,
fluctuating in character between the monitor and crocodile, hides its
reptile nature under the outer form of the bird, but retains the teeth.
To change the skull into a bird's skull it would only be necessary that
a few separate elements should be blended together, and that a few
peculiar bones should be removed. The length of the neck, varying only
in a few species, is a deviation from the reptile type, and indicates
an approximation to the structure of 'the bird; but the number of
the vertebræ remains constant notwithstanding the increased length.
The fundamental plan of the crocodile may be recognised in all the
important parts of the vertebræ. The body of the reptile, to be enabled
to fly, would need a larger breast and a stronger structure of the
fore-limbs. The shoulder-blade of the reptile, with its extremities
forming the glenoid cavity, is necessarily smaller and prolonged
backward, and altered to resemble that of a bird. The scapula only
formed the back part of the glenoid cavity, but it is thick and strong,
suggesting an affinity with the bats.

The breast-bone, in the form of a shield, is changing into that of a
bird; as are the ribs, which are attached in a peculiar way to the
vertebral column. It is really the strong sternum of the Chameleon,
with moveable dorsal vertebræ. The whole chest is supported by the
peculiar continuation of the wings of the pubic bones (Schambein).
The ischiac and pubic bones resemble those of the Chameleon, but the
ilium runs a little down, like that of a bird, and is only slightly
connected with two sacral vertebræ, as in reptiles, prolonging itself
a little upward and forward, as in mammals. The wings of the pubic
bones exist in the Turtle and Monitor, but of small extent; they are
also represented in the mammals by the upward development of the pubic
bones in those families, genera, and species, in which nature has
indicated by variety of shape, or peculiarities of development, or by
affinities with reptiles, quite a new type and capacity for variation
within certain limits, which is especially the case with certain
Rodents and Opossums, and Monotremes. It would not be astonishing to
find in Pterodactyles the marsupial bones. And indeed the Pterodactylus
crassirostris has a small tongue-shaped bone, probably belonging to the
pelvis. The less important part of the skeleton, the tail, is formed
precisely as in mammals, and is identical with that of the bats. Both
the thigh and shin are mammalian, and only the foot retains the same
number of parts as in reptiles.

This animal was enabled by means of the pelvic bones and the long
hind-legs to sit like the squirrels.

We should regard this position as natural but for the long wing-finger
hanging far down the sides. If it were to creep along it would have
the same difficulties as a bat, and the length and weight of the
head, as well as the proportional weakness of the bind limb, make it
improbable that they progressed by leaping. These animals made use of
their claws only to hang on to rocks and trees and to climb up steep
cliffs. They could fly with their wings, and keep themselves aloft in
order to catch insects or sea animals. The wide throat and the weak
and high supports of the jaw-bone make it probable that they only used
their teeth to capture their prey and not to mince it. By means of
their long neck, which they usually bore curved backward in order to
keep their balance, they could stretch out their head to their prey
and change their centre of gravity, and so fly in different positions.
The fundamental type of the Crocodile and Monitor leads us to suspect
that they had a skin covered with scales. The approximation to the
shape of the Bird makes it probable that they were feathered. And the
whole outline, similar to that of the Bat, leads to the supposition
that they were covered with hair, like the Monotremes. Goldfuss thinks
he has got a clear insight into the covering of the body and the whole
condition of the wing in examining the Pt. crassirostris. And the soft
state of the stone near the bones he attributes to the presence of
the soft parts of the animal; and supposes that on the original folds
of the wing-membrane are to be seen tufts and bunches of curved hair
directed downward and sideway[G]. And on the principal slab he finds
evidence that the Pterodactyle had a mane on the neck like a horse.
The tufts on the counter slab have some similarity with the feathers
of the ostrich. Some very tender impressions on both plates still more
resemble feathers. He recognizes the outline and faint diverging rays
of a bird's feather, but never sees a strong quill. The microscope,
instead of making the image clearer, makes it, on the contrary, vanish,
because then the rough parts become prominent. Also on the slab which
contains the Pterodactylus medius[H], are seen numerous lines and
fibres diverging like a bird's feathers. And on the upper part of the
belly is the appearance of a scanty texture of hairs and feathers. The
visible marks of two cylinders of the thickness of a quill, made of
thin substance and filled with limestone, he would regard as quills if
there were clearer marks of their feathers to be seen. As a note upon
this von Meyer says, after examining the slabs, that the particles
considered by Goldfuss to be hairs and feathers rest upon appearances
not only to be seen in the vicinity of Pterodactyles, but which occur
upon many other kinds of petrifactions that have nothing in common with
the Pterodactyle; and that the roughnesses of the slab have nothing to
do with the folds of the wing or the muscles.

[Footnote G: This is represented in Pl. 7, 8 of his memoir, _loc. cit._]

[Footnote H: Pl. 6, _Nova Afta Acad. Leopold_, Vol. XV. Pt. 1.]


Wagner[I]

[Footnote I: _Abhandl. Bayerischen Acad._ 1852, Vol. VI.]

is so convinced that the Pterodactyles are Amphibians approximating
to the Saurians, that he does not think it necessary to go into
any controversy in the matter; but he acknowledges that their
forms sometimes present peculiarities of bird and mammal. The head
especially shows a blending of the bird and reptile types. Its outline,
particularly when seen from above, is that of a long-beaked water-bird.
And the long interval between the nose-holes and the tip of the jaw,
and the peculiar fact of a hole between the nose and eye-holes, and
the want of the continuation of the coronoid of the lower jaw, rather
resemble a water-bird than a Saurian. But the presence and the form
of the teeth show it to be a Saurian; and not only the teeth, but the
configuration of the whole back part of the skull, reproduces the type
of the Monitor. The sclerotic circle is a peculiar mark of birds and
saurians. Very peculiar, however, is the extremely short back part
of the skull; and the articulation of the lower jaw, stretched far
forward and united just under the middle of the eye-hole. The more
or less long neck, which may assume the form of an S, deviates very
much from the short stiff neck of reptiles, and is quite bird-like,
the neck-vertebræ of which those of the Pterodactyle closely resemble
in shape; while their constant number of seven reminds us of mammals
and crocodiles. The neck has the same flexibility as in a bird. The
short and weak trunk-vertebræ are in such disproportion to the length
and strength of the neck-vertebræ as is never met with even in the
birds and mammals which have the longest necks. The trunk-vertebræ
are completely separated from each other, and may be divided into
dorsal, lumbar, and sacral vertebræ. The transverse processes of the
back-vertebræ are notched out like those of the crocodile. The tail
is short in most species, and this is a deviation from the type of
the Saurians, and an approximation to birds and to many mammals. But
there are some kinds with very long tails, as is the case with mammals
and usually with Saurians. But the vertebræ of these long-tailed
Pterodactyles deviate very much from those of Saurians. And while
the Saurian vertebræ are provided with long transverse processes and
upper and lower spinous-processes (Dorn-Fortsätzen), they seem in
the Pterodactyle to be almost devoid of processes and resemble those
of mammals, on the tails of which these processes soon disappear.
In a certain point of view we could say of the vertebral column of
the Pterodactyle, that it has borrowed the neck from the bird, the
trunk from the reptile, and the tail from the mammal. The ribs are
connected to the transverse processes as in crocodiles, except with the
atlas and axis. Quite in the type of the Saurians are the abdominal
ribs, which are wanting to all birds and mammals, but often occur in
the Lacertian order. The structure of the shoulder and breast-bone
separate the Pterodactyle from the mammal, these parts being formed
after the type of the Birds and Saurians, the characters of which are
blended together. The small and elongated shoulder-blade, like the
coracoid bone, belongs to the type of the bird rather than to that
of the Saurians, of which, in reference to the last-named bone, only
crocodiles have a similar one. The breast-bone, by its large expansion,
points to the crocodiles, but at the same time, by the want of the
keel, points to the ostrich-like birds, save that it is proportionally
larger and wider than in these. The Pterodactyle, in common with the
crocodile, wants the patella. The pelvis is formed on the type of the
Saurians, although the ilium, by length and form, points somewhat to
the mammals. The length and delicate form of the long bones of the
limb, as well as the larger development of the fore-arm than of the
upper-arm, and larger development of the lower thigh than of the upper
thigh, and the thinness and elegance and shortness of the ?fibula
(Wadenbein) have the characters of birds. The length of the middle hand
[metacarpals] resembles that of birds, but its form in Pterodactyle
is conformable to that of mammals. The first three fingers have the
form and condition of the phalanges of lizards. The phalanges form the
series 2, 3, and 4. The fourth, or air-finger, on the contrary, is
of a peculiar type, of which no analogue is found in other animals,
unless a somewhat similar arrangement be accredited to the bats. It
is of enormous length, composed of four parts and without a claw.
The hind-leg is, in proportion to the fore-leg, weak, and in general
does not take the bird-form, but that of a Saurian. It has five toes,
with unusual arrangement of the phalanges into the series 1, 5, 4,
3, 2. One toe has no nail, and the others have claws weaker than
those of the hand. It can hardly be supposed that the animal lived
in the water. All Saurians that live either in the water or on land
are short-legged; it is the same with the swimming birds. But the
Pterodactyle has its hind-legs as long as a land or air-bird; and as in
these, the shin especially exceeds the length of the thigh. At the same
time the toes, when they are in their natural position, were so close
together that we may suppose the animal not to have been web-footed.
The great development of the hand, by means of the long middle hand
and especially of the enormous length of the air-finger, makes it
probable that it was the chief organ of flight, as in birds and bats;
also deviating in a peculiar manner from both these types, the long
air-finger served to expand the wing-membrane, which extended from the
upper part of the finger to the trunk, and which in all probability
did not touch the hind-legs. This we infer from the circumstance that
the animal, in a position with the organs of flight folded up, was
not supported like the bat on its four feet, but stood upright on its
hind-legs like a bird. Such a position presumes the same freedom in
moving the hind extremities as with birds; only in such a position
could the animal walk on without being hindered by its flying organs
when they were folded up like those of a bird. Only in such an upright
position could the animal keep upright its unusually long head with the
long and strong neck and be kept in balance, the neck being able to
take a sigmoid curve like that of a bird.

Wagner concludes: "By these means we have recognised in the
Pterodactyle a Saurian, but of a habitude which greatly removes him
from all others of his kind, and approximates him to birds. Excepting
in ability to fly, he has nothing in common with the birds. The opinion
'that the animal is half crocodile half monitor disguised as a bird,
but intending to be a bird,' is therefore not only a paradox but also
false. With more truth, but less phantasy, we could say that the
Pterodactyle was a Saurian in transition to the Birds."


Quenstedt[J].

[Footnote J: _Ueber Pterodactylus Suevicus._ Tubingen 1855.

In the long thigh, with the long neck, Quenstedt sees evidence that the
animal was able to walk upright, being probably still more upright than
birds, since the great disproportion between the neck on the one hand,
and the thigh on the other, could not have allowed a more appropriate
position. At the same time he makes a question, Did it go on four feet?
But a little later, in his book, _Sonst und Jetzt_, 1856, he gives
a sketch of the animal resting on its four legs; and remarks, "The
position upon four feet is however hypothetical, but is probable. It
had its wings folded back. The slightly curved and thin bones of the
middle hand probably served to support the flying-membrane, and had
therefore the same function as the spur-bone in the bats." Finally, he
says in his book, _der Jura_, p. 813, "Perhaps this animal walked from
time to time on four legs, being then supported by the fore-end of the
metatarsal bone."]


Burmeister[K].

[Footnote K: _Beleuchtung uniger Pterodactylus arten._ 1855.]

entirely rejects Quenstedt's opinions with regard to their upright
position. He makes the following remarks: 'The animal walked on the
free fore-toes and bore the wings like a bat, though with the body not
in an upright position like a bird, but four-footed. The hind-foot is
much too small for such an upright position, and the fore-foot much too
strongly developed. I therefore believe that the Pterodactyle could
much better have walked four-footed than a bat, because it possessed so
much better developed fore-feet.' In the length of the tibia Burmeister
sees no reason for the upright position, but, as he says, only a means
for the wide expansion of the flying-membrane;--and an endeavour in
walking on four feet to bring the leg into the necessary harmony with
the arm, which is so much elongated with the flat-hand.


Hermann von Meyer[L].

[Footnote L: _Fauna der Vorwelt. Reptilien aus dem Lithographischen
schiefer._ Frankfurt am Main. 1859. pp. 15-23.]

The skull of the Pterodactyle can only be compared with those of
birds and lizards. The form is essentially Avian, and the sutures are
indistinct or obliterated as in birds, while in reptiles they are
persistent The temporal bone enters into the formation of the reservoir
for the brain, which is eminently characteristic of birds and quite
different from anything found in lizards. The snout resembles a bird in
being chiefly formed by the intermaxillary bone, which bounds the front
of the anterior nares; and, as in birds, the bone extends backward
between the eye-cavities to the frontal bone. The corresponding
intermaxillary ridge of the Monitor is of less extent.

The frontal-bone forms the highest part of the skull, and is similar
to that of birds. The principal frontal is double, and forms the upper
and hind part of the cavity for the eye, and covered the greater part
of the large brain, composed of two hemispheres, in which Oken long
ago saw a similarity to the higher animals. The arched form of the
back part of the skull is bird-like. The double parietal adjoins the
principal frontal, and is conditioned like the parietal in birds. The
supra-occipital is single as in birds, expanded, and forms the part of
the skull which extends furthest back. From the form of the back part
of the skull it may be concluded that the foramen magnum was situated
as in birds, and that the head and neck were moved as in birds, and not
as in reptiles and mammals.

The temporal bone rests upon the parietal and frontal, and forms much
of the temporal foss. Its anterior border does not appear to enter
into the margin of the orbital cavity as in birds, but seems to be
replaced by the post-frontal, which resembles that of the Chameleon.
Its hindmost branch, which can hardly be supposed to be the jugal,
forms the outer boundary of the temporal foss by uniting with a process
which is probably part of the mastoid. A similar closing of the cavity
for the temporal muscles is also to be found in birds. The jugal
and maxillary do not follow the bird type. The jugal consists of a
single bone which forms the greater part of the anterior and inferior
boundary of the cavity of the eye, which is surrounded with bones, as
in Dragons and Iguana. In those birds in which the cavity of the eye is
surrounded with bones the jugal does not enter into it. As in lizards,
at its upper end the jugal is commonly connected with the lachrymal,
which bone is like that of a bird. A bone, which appears to be the
pre-frontal, enters into the back of the nasal aperture.

The nostril is double and often of large size.

The perforation in the skull between the orbit and nares is bird-like.

The quadrate bone is not quadratic as in birds, but cylindrical and
shaft-like, as in the Chameleon. The articulation of the quadrate with
the lower jaw is placed further forward than in birds and reptiles. The
lower jaw, but for the teeth, has great similarity with that of a bird.
Among reptiles its nearest resemblance is with Chameleons and Turtles.
The hyoid is more bird-like than reptile-like.

_Ribs and vertebræ._

It is uncertain whether the Pterodactyle had lumbar vertebræ. If they
are wanting, therein the animals resemble birds, of which we are
reminded in the short and stiff back and moveable neck. Pterodactyles
possess a smaller number of neck-vertebræ and a larger number of
back-vertebræ than birds. The long neck-vertebræ are paralleled by
those of water-birds, by the Giraffe, the Camel, Protosaurus and
Tanystrophæus. There are 7 cervical vertebræ, the 1st very short, 2nd
not longer, but rather shorter than those which follow. There are in
Pterodactyles from 12 to 16 dorsal vertebræ, while birds have never
more than 11. It is not certain whether all Pterodactyles have an os
sacrum; most have it, and therein resemble Mammals, Birds, and some
fossil Saurians. In Pterodactylus dubius and P. grandipelvis and P.
Kochi there are 5 or 6 vertebræ in the sacrum. In birds the sacral
vertebræ vary from 5 to 22; in bats the number is from 5 to 6.

The short tails of Pterodactyles are more like those of mammals than
birds; they include from 10 to 15 tail-vertebræ. In birds there are
from 6 to 10 tail-vertebræ. Rhamphorhynchus has 38-40 tail-vertebræ,
secured between thread-bones like those in the tail of rats.

The dorsal ribs are reptile-like. In herbivorous mammals and birds
they are broader. A few species have the first pair of ribs large. The
abdominal ribs belong neither to birds nor mammals, but are reptilian.
In Rhamphorhynchus Gemmingi there are 6 pairs of sternal ribs.


_The sternum_

is bird-like, somewhat resembling lizards. It consists of a simple
flat bone, but without the keel of a bird's sternum. It is relatively
smaller than in birds, is broader than long, and therefore comparable
with Struthious birds. They were not able flyers, since the part to
which the muscles for flight should be affixed is wanting. And for
the same reason they could not have been wandering animals. But Moles
possess a keel on the breast-bone, which therefore is no evidence
of flight. And in swimming-birds which do not fly the keel is much
developed; and in swimming-birds the sternum is also long, so that
neither length nor keel prove flight. So far as the evidence from the
sternum goes, they were neither water-birds, nor diggers, but denizens
of the air. In Rhamphorhynchus Gemmingi, besides the usual breast-bone,
there is a plate with breast-ribs uniting the sternum with the dorsal
ribs; they are cartilaginous, or horny, as in birds.


_The scapula and coracoid_

present the closest resemblance with those of a bird, and only deviate
in the coracoid not being inserted in the breast-bone in the manner
of birds[M]. It at first seemed that Rhamphorhynchus differed from
Pterodactyle in having the scapula and coracoid anchylosed. In R.
Gemmingi the bones are either separated or only slightly united.

[Footnote M: See however Pl. 1 and 2 of this memoir.]

Oken and Goldfuss thought that the scapula consists of an upper and
under part, as in lizards. Von Meyer sees nothing of the kind.


_The humerus_

presents no striking similarity with birds, and differs from bats.


_The carpus_

is more reptile-like. It consists of two rows of small bones. In birds
there is one row made up of two bones.


_The pteroid bone._

Von Meyer regards it as having supported the wing-membrane in flight.
There has been a good deal of difference of opinion about it, some
thinking it, with Quenstedt, an ossified tendon; others, like Wagner
and Burmeister, regarding it as an essential part of the Pterodactyle
skeleton. Von Meyer regards its extent as indicating the extent of the
wing-membrane. See p. 42.


_Metacarpus._

In length the metacarpus resembles that of the Ruminants, in which
however it consists of but one bone; while in Pterodactyles there is
a separate bone for each of the four fingers; they are closely united
together without being blended. In some Pterodactyles the metacarpals
of the short fingers are as fine as hairs, so that it is impossible
that they should have articular facets on the carpus. In Ornithopterus
the metacarpus has some resemblance with that of the bird, but the
articulation with the phalanges of the finger for flight is stiff. In
Pterodactylus and Rhamphorhynchus there is a free articulation.

Burmeister remarks that the chief articulation of the wing in bats is
with the carpus, while in Pterodactyle the articulation is with the end
of the metacarpus.


_The hand._

Von Meyer finds four fingers. It was formerly supposed that the order
of the phalanges was 2, 3, 4, 4, but in the fly-finger this is not the
case, Ornithopterus having but two. The number of joints in the other
fingers is quite as irregular.

In Pt. longicollum the thumb consists of but one joint.


_The Ilium_

is more mammalian and avian than reptilian.


_Pubis._

The pubis appears to have been excluded from the glenoid cavity, as
in Crocodiles. It is more mammal-like than bird-like, and is to be
compared with the marsupial bones.


_The femur._

In certain Pterodactyles the proximal condyle of the femur resembles
birds; but in other Pterodactyles the bone is more mammal-like in its
straightness, and development of the upper condyle, and in the presence
of a trochanter.


_The tibia and fibula_

may be compared, from their great length, with birds and flying
vertebrate animals.

The fibula is style-shaped, like that of a bird, the lower part being
wanting; while in bats the upper part is wanting.


_The tarsus,_

of two rows, is best compared with that of reptiles. The number of
constituent bones has not been definitely determined.

_The metatarsus_

shows a certain return from the bird type to that of reptiles.


_Foot._

Von Meyer never finds more than four toes, and sometimes a stump of a
fifth. As a whole, the foot is Saurian-like. It differs from lizards in
the number of toes, and approximates to Crocodiles. In Pterodactylus
longirostris the formula of the toes is 2, 3, 4, 5, with a stump of two
joints;--like lizards, if we abstract the outer toe; and like birds
with four toes; but they are liable to variations.

In Pterodactylus scolopaciceps and P. Kochi the formula is 2, 3, 3,
4 joints. In Winkler's specimen of P. Kochi there is also a stump of
three joints.

In Pterodactylus micronyx the formula is 2, 3, 3, 3, and a stump of two
joints. In P. longicollum the number appears to be different from all
the foregoing.

The stump was attached to the side of the outer toe. Wagner, in P.
Kochi, supposed it to be on the inner side, and so gave a reverse
arrangement to the toes. The stump may be compared with that of some
Chelonians, in which it is not furnished with a claw.

There is a difference from birds in the claws being much less
developed. It has a true reptile foot. In bats the toes are of equal
length. Von Meyer thinks the hind-legs did not enable it to walk on the
land.

In some Pterodactyles the flying-membrane is faintly seen. The presence
of feathers might be inferred from there being but one finger for
flighty as in birds; but the function of feathers is subserved by the
long and stiff finger. If it had been covered with scales, as was
supposed by Cuvier, some traces of them would be found. The skin was
probably naked, and had no connection with the hind-legs as it has in
bats; in this respect resembling birds.

The condition of the several parts of the skeleton completely proves
that the Pterodactyle was a reptile. Its head, neck, shoulder, and
back, resemble a bird; while there are, on the other hand, some
striking resemblances with the reptile in the pelvis, tail, and
articular parts of the limbs. Sometimes the characters of the two
classes run side by side, as in the skull, the fore-limbs, and
especially in the hind-limbs, where the shin of a Bird is connected
with the foot of a Saurian. The parts in which it corresponds with
birds show that Pterodactyles also were flying animals. That we should
be entitled to conclude, from the hollow state of the bones, that they
belonged to flying animals, is sufficiently proved by Blumenbach,
Buckland, Mantell, Owen having mistaken them for bones of birds.

The most absolute proof that it was a flying animal is the pneumatic
character of its bones. This condition was discerned by me in some
Pterodactyle bones from the Lias of Franken (_Jahrb. für Mineral_,
1837, p. 316), and was afterwards established by Owen in the
Pterodactyles from the Chalk of England. This structure was previously
only known in birds. And the supposition readily follows that in the
respiratory process there was some similarity between the Pterodactyle
and the Birds. They have the proportions of upper-arm and fore-arm
which characterize birds of great flight, the humerus short and the
fore-arm long; hence it may be presumed that Pterodactyles could fly
well. From the absence and presence of the bony sclerotic ring in the
eye, it may be supposed that the Pterodactyles were active in the
day-time, while Rhamphorhynchus was nocturnal.

After this statement von Meyer gives a discursive summary, in which his
views of the classification of reptiles in general and of Pterodactyles
in particular are epitomized. And then goes on to combat the views of
people who have departed from his classification and attempted to set
up classifications of their own; and cites a number of authors who,
labouring at the vertebrata, have endeavoured to find a resting-place
in their systems for the Pterodactyle. But the chief thing we learn of
von Meyer's own views is, that in 1830 he published a classification of
extinct Saurians, dividing them into those with limbs like the larger
and heavier land-mammals, those with fin-like limbs, and those with a
flying-finger. Which divisions have been widely adopted, though authors
have sometimes given them other names than those by which they were
first made known.

Von Meyer has freely stated the facts about the Pterodactyle, and draws
the conclusion that the animal was a reptile; but how such a conclusion
was obtained from such facts is a matter on which his pages are silent.
One seems to hear the chirrup of the bird in almost every paragraph.
The head is in the main a bird's head; the pectoral girdle and the
sternal ribs are those of a bird; and very few are the structures in
which some reminder of the bird is not present; and in their bones he
discovered the pneumatic characteristic and inferred, for the animals
bird-like lungs. How, then, comes it that the Pterodactyle is a
reptile? We can only suppose the answer to be, Because if the head and
pectoral girdle and other bones had been reptilian it would have been a
bird.

       *       *       *       *       *

In the views here epitomized it is difficult always to make out the
logical foundations of the conclusions arrived at. Sometimes they have
no foundations, and sometimes they represent the different aspects
in which a truth presents itself to minds differently constituted
or differently conversant with the structures of living animals. In
now stating my own views I shall avail myself of the example of some
previous writers, and attempt to investigate the Pterodactyle as though
they had not written. And then, having placed before him all the
theories that are known, the reader will be able to choose the theory
that pleases him best, if indeed he needs one.

Much of the discrepancy of opinion that exists is probably due to the
use of the inductive method of thought for the discovery of fundamental
principles in classification. In palæontology, where the types are
more generalized than are living forms, it must always be difficult to
reason from the known to the unknown. The known is always more or less
incomparable with the unknown; and there can be no reason for inferring
that the specialities of structure which now accompany specialities
in organization would justify us in inferring for the animal, in which
the structures formerly were united, the combined organizations of
the living animals in which they are now found. On any hypothesis
of evolution it would be allowed that the special modifications of
a group were attained subsequently to the common plan of the larger
group to which it belongs, and are entirely to be attributed to the
function which the necessities or organization of the animal caused
its structures to subserve. Inductive thought may sometimes discover
function from structure, but never makes more than an approximate
guess when it endeavours to determine fundamental organization from
osseous structures which are not fundamental. And before a naturalist
can say, since an animal has for instance a tail like a mammal that in
so far it must be affiliated to the mammalia, he must have determined
why the mammalian tail has its peculiar characters, and whether it is
compatible with any other common plan of organization. And perhaps it
might with equal reason be considered reptilian.

Therefore I prefer at firsts instead of reasoning from the details
of structure, to adopt the _à priori_ method, and ask, not what the
Pterodactyle is like in its several bones, but what common plan it had
whereon its hard structures were necessarily moulded. For I imagine, if
it can be determined what the nervous and respiratory and circulatory
structures of the Pterodactyle were, it becomes a secondary matter to
know whether the phalanges are like a lizard's, or the pelvis like that
of a mammal. If the animal is asserted to be a mammal, a reptile, or a
bird, we ought to be able to adduce evidence that it had the soft parts
which are deemed distinctive of the selected class. This no one has
done or attempted to do.

Hereafter it will be necessary to describe the Pterodactyle's brain.

There is no organ more distinctive between hot-blooded animals on the
one hand, and cold-blooded animals on the other, than the brain. In
the cold-blooded groups, or those in which respiration is feeble and
circulation imperfect, that is to say, in existing fishes, amphibians,
and reptiles, the parts of the brain are arranged one behind another,
so that when looked upon from above, a portion called the optic lobes
intervenes between the anterior masses called the cerebrum and the
posterior mass called the cerebellum. In the hot-blooded groups, or
those with an enormous extent of lung-surface for oxidation of the
blood and a four-celled heart for its rapid circulation, that is to
say, in birds and mammals, the front part of the brain called the
cerebrum is immensely developed in proportion to the other parts,
and abuts against the cerebellum and more or less completely covers
the optic lobes, which in birds are squeezed out to the sides. The
Pterodactyle brain is of this latter kind. And it being taken as a
postulate that this kind of brain is the product of the organization
which produces hot blood, it follows that the Pterodactyle was a
hot-blooded animal.

Again, the Pterodactyle has perforations for pneumatic cells in many of
the bones.

There is no structure in the animal kingdom more distinctive of a
Class of animals than air-cells perforating the limb-bones. They are
connected with a peculiar kind of lung and heart--those of the bird;
for in this Class the bronchial tubes open on the outer surface of
the lungs into air-cells, which are prolonged through the body into
the bones. They follow the blood-vessels, and are most developed in
the part of the body most used. In some lizards, as the Chameleon,
the sack-like lung at its distal termination is as simple as the
air-cells of a bird; but those air-cells are not comparable with the
bird's air-cells, since they are not prolongations of the bronchial
tubes through the walls of the lungs. And it cannot be inferred that
a reptile with wings would develop air-cells like those of a bird:
in the first place, because those mammals which have wings do not
develop air-cells; and, in the second place, because there is nothing
in existing nature to lead any one to think that reptiles might have
wings. The mammalian lung is better comparable to that of a bird than
is the Chameleon lung, and therefore the air-cell structure might
with better reason have been anticipated to occur in the Chiroptera
than in a Lizard-ally, if it were dependent on the development of
wings. Moreover, among Struthious birds the legs have more of the
air-cell prolongations than the wings. Therefore, being a peculiar
Avian structure which only exists in association with the Avian heart
and lung, it follows that because the Pterodactyle had the pneumatic
foramina it also had the structures of which they are the evidence,
viz. lung and heart formed on the bird plan.

Thus Pterodactyles have a nervous system of the bird type. That kind of
brain only exists in association with a four-celled heart and hot blood.

They have a respiratory organization which is only met with among birds.

With that respiratory apparatus is always associated a four-celled
heart and hot blood, which it would necessarily produce.

And with that respiratory organization is always associated a brain of
the type that the Pterodactyle is found to possess.

_Therefore it is firmly indicated that the general plan of the most
vital and important of the soft structures was similar to that of
living birds._

This proposition will be incidentally proved in the following memoir,
in which it will be seen that with such a common plan, is associated a
diversity of details sufficient to demonstrate that these animals are
not birds, but constitute a new group of vertebrata of equal value with
the birds--the sub-class, Ornithosauria.




                        OSTEOLOGICAL COLLECTION


               ILLUSTRATIVE OF THE MODIFICATIONS OF THE
                ORNITHOSAURIA (OR PTERODACTYLES) IN THE
                      CAMBRIDGE UPPER GREENSAND.


  Pectoral Girdle.

  STERNUM.

  Pl. 1, fig. 1.

  Case. Comp. Tablet.
   =J=     _a_      1

The Sternum is the key to the bony apparatus supporting the anterior
limbs. In the Pterodactyles from the Cambridge Greensand it has been
well figured and described by Professor Owen, who enunciated its
resemblance to the sternum of birds. The sternum in Pterodactyles from
the Lithographic Slate, shows its proportional size to the body. The
examples found in the Cambridge Greensand have as yet shown no evidence
of a composite character like that attributed to Rhamphorhynchus
Gemmingi.

The sternum consists of an expanded symmetrical shield having its
lateral halves, which are inclined to each other at a large angle
(about 150°), contracted superiorly, behind and immediately below the
synovial cavities for the coracoids. The vertical angular ridge in
which the lateral portions of the sternum unite becomes elevated as it
is followed anteriorly, into a strong keel. This keel or interpectoral
process is highest in front of the articulations for the coracoids; but
the degree of elevation varies with the species. It is prolonged upward
and in front of the coracoids for some distance, becoming very massive,
and the prolonged mass which is flattened from side to side, reaches
laterally to the outer margins of the coracoid articulations, and on
the visceral side a little between and over them. The anterior crest of
the keel shows the attachment of powerful muscles.

Professor Owen has observed that only in birds are distinct synovial
cavities provided for the coracoids, and that no reptile has a
sternum showing characters like those seen in the Pterodactyle. These
coracoid cavities are placed as in birds, close together, behind the
_manubrium_, which forms the hindermost part of the keel. They are
convex transversely, concave from front to back as in birds, and
look upward at an angle of 35°, their main direction being outward
and a little backward. Professor Owen recognises the function of the
shield-shaped sternum in relation to the mechanism of respiration on
the one hand, and on the other hand, for the attachment of pectoral
muscles of great bulk and strength.

As is well known, the muscles of the breast in most birds consist
chiefly of the 1st, 2nd, and 3rd pectoral muscles, and the
coraco-brachialis.

The peculiar form of the bird's sternum appears to be due to the
vertical development of the second pectoral muscle, since when the 1st
and 3rd muscles are dissected off, the appearance presented nearly
resembles that of the sternum in Pterodactyles. There can however be
no doubt but that the third pectoral muscle, which in most birds is
but feebly developed, attained a far greater bulk in the Pterodactyle,
because there is evidence of its powerful insertion in the distal
anterior face of the coracoid, as well as of the great lateral
extension of the sternal shield to which such a muscle must--by the
analogy of birds--have been attached. The peculiar lateral emargination
of the sternum appears to be due to the anterior sternal termination of
this muscle, caused by the outward direction of the coracoid bone.

Since the coracoids were developed outward and backward so much more
than in birds, it would happen, from the apparent different direction
of the second pectoral muscle, that the first pectoral muscle which in
birds skirts the furculum, must have passed over the coracoid, probably
pulling on its inside in opposition to the third pectoral. Either a
subdivision of this muscle or a distinct muscle in the same place, in
function corresponding to the subclavius muscle, appears to have been
powerfully attached from the anterior prolongation of the keel of the
sternum to the front face of the coracoid. It is improbable that the
second pectoral muscle was undeveloped, but merely directed differently
to what it is in birds, since, as will be seen, there is a process at
the proximal end of the coracoid homologous with that which forms the
pulley round which this muscle in birds works.

Professor Owen concludes his remarks by observing that the Pterosaurian
breast-bone is in the main formed on the ornithic type. The muscles
also appear to be similar to those of birds.

All the specimens are much mutilated, but all show the distinctive
post-coracoid lateral emarginations, but as these are not seen in
German Pterodactyles they are to be regarded as characters of a
peculiar sub-order and not as characteristics of the sub-class.

The example figured in this memoir and by Professor Owen is 2-5/8
inches in antero-posterior measurement, probably about one third its
entire length.

A small example in the collection of Mr Reed of York extends 1-1/4
inch in the same measurement, and by the analogy of _P. suevicus_ was
more than twice that length when perfect. It is remarkable in that the
coracoid facets look much less outward and much more backward than in
the larger species.

The mammalian sternum is usually in many consecutive pieces like the
vertebral column. The types in which it attains any size as an expanded
shield are Cetaceans and the Manatee, but in these groups it has no
keel and is not connected with the other bones of the pectoral girdle.
The proximal portion of the sternum of the Mole is elongated and
bird-like, with the shield narrower than in the typical gallinaceous
birds, and with the keel similarly developed. It is connected with the
humerus by small sub-quadrate bones named clavicles placed at the sides
of the proximal end. The sternum in Bats usually consists of a proximal
and a distal part. It is narrow except at the proximal-termination
where it widens like the letter T or Y; and to the sides of the lateral
prolongations are attached the long, slender, curved bones named
clavicles, and a pair of ribs. This sternum develops a bird-like keel.
Both Mole and Bat are regarded as differing from Pterodactyles in the
bone giving attachment to the clavicles instead of to the coracoids.
The proximal part of the sternum in both the living animals, gives
attachment to but one pair of sternal ribs. The Pterodactyle sternum
otherwise differs from the Bats in having the articulations for the
coracoids close together, of a peculiar concavo-convex character, with
a massive portion or keel prolonged forward in front of the coracoid
articulations. The Bat cannot be said to resemble the Pterodactyle
closely. The sternum of the Mole differs from that of the Pterodactyle
in having a less developed shield, and in having a more developed keel
which is not prolonged in front of the coracoid articulations. These
examples demonstrate that resemblance in conformation is functional,
and no proof of affinity.

Pterodactyles make some approach in the proportions of their sternum
to Struthious birds. But the Struthionidæ have the bone thick, do
not develop a keel, nor, have they an inter-coracoid process while
the coracoid articulations are singularly long and narrow instead
of being ovate. With other birds the Pterodactyle sternum agrees in
giving attachment to the coracoid bones by synovial articulations, in
the bone being shield-shaped, and supporting a more or less developed
keel. The keel is chiefly developed at the proximal end, as in the
Albatross, which has the bone broad; and it is prolonged in front of
the coracoids exactly as in _Mergus merganser_, which sternum if a
little broader in the shield and thicker in the keel would very nearly
reproduce the sternum of the Pterodactyle, even to the "post-coracoid
lateral emargination" of Cambridge specimens. Among reptiles the only
form which suggests comparison is the Chameleon, in which however the
sternum consists of an anterior and a posterior part as in the Bats,
the back part narrow, and the front part a long lozenge shape, with
a keel made by inclination of the sides of the bone to each other as
in the Dodo, but the keel such as it is, is at the back part of the
bone, and there is no prolongation in front of the coracoids as in
Pterodactyle. The coracoids are broad, and are applied to the two
anterior sides of the lozenge. The Crocodile has a narrow flat sternum
which is prolonged anteriorly between the coracoids.

The resemblance is greater with mammals than with reptiles. From birds
the Pterodactyle sternum makes no essential difference, and in the
Merganser finds a close ally.


  CORACOID.

  Pl. 2, fig. 1-6.

  Case. Comp. Tablet. Specimen.
   =J=   _a_     2      1-23

Commonly the coracoid in the Cambridge Pterodactyles is anchylosed to
the scapula: occasionally the bones are separate, though the separation
has hitherto only been observed in the largest species. In 1851
Professor Owen, when figuring the anchylosed ends of the scapula and
coracoid in Pterodactylus giganteus (Bowerbank), observed that in no
part of the skeleton does the Pterodactyle more nearly resemble a bird
than in the scapular arch; a view again urged emphatically in 1859 when
similar fragments were described from the Cambridge Greensand. Since
then perfect examples of the coracoid have occurred, which show the
characters given in the following description.

The bone is long, with sub-parallel sides, sub-triangnlar in section,
with the proximal end expanded exteriorly and posteriorly, resembling
in form the coracoid of a bird. The front surface looks forward and
outward; it is flattened, is a little convex transversely, and a
little convex in length; it is rugose with muscular attachments, which
terminate in a tubercle on the uppermost fourth of the front, usually
near to the inner side. The middle third of the slightly concave
inside margin of the front aspect, is sharply angular; the parts above
and below it have the angularity rounded off. The outside margin, a
little more concave than the inside margin, is sharply angular in its
distal third, in which the front gradually widens to near the sternal
articulation, when it contracts--the whole sternal termination of
the bone being directed a little inward towards the manubrium of the
sternum. The inside, which faces the opposite coracoid, is convex
transversely in the lower half or two-thirds; its distal termination is
carried inward. The expanded proximal end of the inside is flattened,
or channelled, by the developement inwardly, at the proximal end
of the ridge formed with the front side, of a long strong process
homologous with that on the inner side of the coracoid in birds. The
channel so formed rounds on to the proximal surface of the bone, and
extends backward to the limit of the scapula; over it the second
pectoral muscle may be presumed to have worked[N]. The third side of
the bone is much more concave in length than either of the others;
it looks backward, outward, and downward, the proximal end being
turned outward and downward more than the distal end; it is a little
concave transversely at the expanded proximal end. Near the distal
end there are sometimes visible a few faint marks of the insertion of
muscular fibres, but they are much less distinct than those made by the
coraco-brachialis muscle in the corresponding region of the coracoid
in birds. Throughout its length it rounds into the inner side, and the
upper third rounds convexly into the front. On the most posterior part
of this aspect of the proximal end is a groove terminating in a long
pneumatic foramen, partly in the coracoid, partly in the scapula.

[Footnote N: The homologous process is more developed in Pterodactylus
giganteus. See f. 7. pl. XXXI. Owen, Cret. Rept.]

The muscular attachments on the front aspect of the coracoid appear to
be two; one large and long inserted into the inner half of the middle
third of the bone, terminating at the proximal end in a tubercle. No
specimen shows the distal end of the insertion. This may indicate a
subdivision of the first pectoral muscle. The other insertion, if it be
distinct, is long and much narrower and at the distal end of the bone.
This, according to the analogy of birds, should be the third pectoral
muscle; if the insertion should be but part of that to which it is
distally adjacent, then the third pectoral muscle must have had an
enormous developement unparalleled in birds.

The distal end of the bone terminates in a synovial articulation
concave transversely, convex from front to back, in form transversely
ovate: the narrow side of the articulation, like the thin edge of the
coracoid, being exterior. The articulation is about three fourths of
the transverse diameter of the distal end; it is at right angles with
the long axis of the bone, and looks downward and a little backward.

The proximal end, massively enlarged outward and backward, presents on
the proximal surface three well defined regions. The largest of these
is an irregular flattened surface half ovate in form, inclined to the
axis of the bone at about 45°, looking backward, and upward also,
when the bone is held vertically; the mesial hindermost half of the
radius of this area is occupied by a pneumatic cavity: to this surface
is applied the scapula. The next largest surface is rectangular and
oblong, looking upward, outward, and a little forward. The transverse
aspect which looks outward being nearly half as long again as the
antero-posterior aspect which looks forward; in the latter direction
the area is slightly concave, in the former direction it is slightly
convex; its posterior boundary is parallel with the front of the bone:
this area forms the anterior moiety of the glenoid cavity, to which the
proximal end of the humerus is applied.

The remaining surface of the proximal end is sub-quadrate, adjoins the
two other surfaces as well as the front and the inside of the shaft, it
is conically concave.

The entire bone when applied to the sternum looked outward, backward
and upward.

Professor Owen remarked (1859) that the "coracoid is shorter and
straighter in birds than in Pterodactyles, but is commonly broader, and
with a longer and stronger anterior process."

The points in which the Pterodactyle coracoid resembles that of
birds (e. g. Gallinaceæ) are the long slender triangular shaft; the
concavo-convex articulation to the sternum; the convexity of the distal
end in front, and its concavity behind; the posterior aspect of its
scapular surface, and the pneumatic foramen.

The points in which it is distinct from birds are that the bone is
not produced proximally beyond the glenoid cavity for the humerus,
which, instead of being lateral as in birds, and looking outward,
in Pterodactyles forms the proximal-termination of the bone. The
sternal articulation is proportionally much shorter transversely in
Pterodactyles, terminating in a convex margin which rounds up into the
thin outer margin, as in the immature coracoid of the common Cock.
It is bow-shaped in front instead of being straight, and is commonly
longer than in birds. The usual ossified connection with the scapula
is not entirely unparalleled in birds, the whole pectoral girdle being
sometimes anchylosed into a bony mass as in the frigate bird.

In the monotremata, the only mammals in which the coracoids are
separate bones, they rather recall those of Ichthyosaurus than those of
any other animals, and have no connection with the sternum. The bone
which represents it functionally in placental mammals is the clavicle.

In no reptile is there any structure resembling the Ornithosaurian
coracoid. The nearest approximation is made by the Crocodile, in which
as in the Chameleon the pectoral girdle is formed as in pterodactyles
and struthious birds by scapula, coracoid and sternum. But in the
Crocodile the coracoid is compressed, and expanded from side to side
both proximally and distally. Distally it has no synovial articulation
with the sternum; and proximally a wide process of the bone extends
beyond the articulation for the humerus as in birds, only the scapula
unites with the prolonged part, and the glenoid cavity looks forward
and inward.

The coracoid is essentially avian in its affinities, though with
peculiar characters of its own. In the German genera it closely
resembles specimens from the Cambridge Greensand.

23 specimens are exhibited. Nos. 4, 10, 12, are the middle parts of
shafts of left coracoids. Nos. 3-12, 22, are the middle parts of shafts
of right coracoids. Nos. 2, 5, 14, are proximal ends of left coracoids.
Nos. 1, 6, 8, 9, 23, are proximal ends of right coracoids. Nos. 15,
16, 17, 18, 19, 20, 21, are distal ends of left coracoids. No. 13 is a
nearly perfect left coracoid, and No. 7 is the glenoid cavity for the
humerus formed by a right coracoid with the anchylosed scapula.


  SCAPULA.

  Pl. 1, figs. 2-12.

  Case. Comp. Tablet. Specimen.
   =J=   _a_      3      1-17
                  4      1- 6
                  5      1- 4

Professor Owen described the scapula of Pterodactylus giganteus in
1851, and added further particulars regarding the Species from the
Cambridge Greensand, in 1859; but, as with the coracoid, only the
humeral end has hitherto been figured. The only example sufficiently
perfect to give the length and proportions of the bone is preserved in
the collection of Mr Reed, of York. This left scapula is a stout strong
bone, short in proportion to its strength, of flattened ovate form in
section, expanding at the humeral end into an irregular sub-rhomboid
mass. It is smaller in the middle, contracting both from side to side
and from back to front till the back to front measurement is 7/16 of
an inch, and the side to side measurement is 11/16 of an inch, and
it expands a little at the free end, which terminates in a smooth
heart-shaped surface, convex in the long diameter, which measures 7/8
of an inch, and flat in the short one, which measures nearly 5/8 of
an inch; it is at right angles with the inside of the bone. The sharp
superior lateral outline is concave, but less so than the inferior
lateral outline; into that inferior aspect of the bone the sides are
more fully rounded. The flattened inner surface applied to the ribs is
concave in the length of the bone, which measures 3-1/2 inches; the
posterior half of which is convex transversely, the anterior humeral
half is concave transversely so as to be cup-shaped, and measures in
extreme width 1-11/16 inch; the outline of the transversely convex
outer side in length is nearly straight, but the exterior part and
glenoid cavity of the proximal end is broken away, and there only
remains a small median proximal sur&ce broken at both ends, a little
concave in length, measuring 5/8 of an inch, and convex in breadth
measuring 1/4 of an inch.

As there is no specimen in the Woodwardian Museum showing clearly the
connection of the proximal with the distal end, the specimens are
arranged on separate tablets.


Humeral End of Scapula.

The humeral end of the scapula exhibits in the different species much
diversity of form, spreading laterally from the shaft, and terminating
in an elongated articular surface truncating the bone nearly at
right angles. On its inferior border it throws out a large convex
tuberosity, separated from the humeral articular surface by a deep
emargination. From the tuberosity usually arises a crescentic row of
muscular insertions, which is continued inward and forward over the
most compressed part of the scapula towards the middle of the humeral
articulation. From the superior margin, interior to the coracoid,
arises a prominent ridge, the spine of the scapula, which is directed
diagonally backward and downward, terminating in the middle of the
outer surface, where it is bordered on the anterior aspect by a long
narrow muscular attachment. Between this spine and the elevated margin
of the glenoid cavity the bone is much compressed and concave.

On the inside surface of the bone there appear to be small muscular
attachments in front of and behind the great tuberosity. The area
between the spine and the inner surface is sometimes flattened,
sometimes gently convex.

With well-marked distinctive characters in the inferior tuberosity,
the pre-tuberous emargination and the thick rounded form of the bone,
the Pterodactyle scapula is intermediate in character between that
of a mole, a bird, and the crocodile; wanting the sabre shape of the
bird's scapula, it also wants the wide expanded form of the scapula of
the Crocodile, but resembles the latter in the direction and degree of
developement of the spine. This modification is probably due to the
outward direction and clavicular function of the coracoid, as well as
to the raptorial habit of the organism.

In no living Reptile is there a scapula to be compared with that
of the Pterodactyle, for besides the free end being expanded, in
the crocodile, it is also thin and squamous and the bone makes a
continuous curve with the coracoid as in struthious birds, and not a
sharp angle as in Pterodactyles. The "spine" in crocodiles is on the
anterior border of the bone and directed upward and backward, while in
Pterodactyles it is on the posterior border and directed upward and
forward. In the Chameleon the scapula is more elongated and narrow,
narrower in proportion to its length than in Pterodactyle, but becomes
rapidly wide at its union with the coracoid. It is curved in length so
as to fit on to convex ribs. A scapula presenting some resemblance to
Pterodactyle is found in certain Liassic Ichthyosaurs.

Among mammals a straight elongated narrow scapula is rare. The mole
however has a scapula of this kind somewhat cylindrical in its proximal
half and not much expanded at the free end, on which there is a
small spine. The anterior emargination above the glenoid cavity in
Pterodactyle is entirely mammalian, as is the anterior tuberosity above
the emargination, for it entirely corresponds with what in ruminants,
pachyderms and many mammals would be named the coracoid process. If
that process is accurately determined it is difficult to say what this
is.

In birds there is often a prolonged process on the inner side of the
coracoid, which however extends interior to other parts of the scapula,
and to this the furculum is attached. Such traces of a spine as are to
be detected in the swan conform to the Pterodactyle.


No bird has the scapula cylindrical, even struthious birds only making
an approximation to such a condition; and no birds have the scapula so
straight. The bone is more avian and mammalian than reptilian; and
more avian than mammalian but with strong distinctive characters of its
own.

17 specimens of the humeral ends of scapulæ are exhibited. Nos. 1, 4,
6, 7, 8, 9, 11, 13, 14, 15, 17 are left scapulæ. Nos. 2, 3, 5, 10, 12,
16 are right scapulæ.

The tablet of the distal ends of scapulæ comprises 6 specimens.


Fore-Limb.

  HUMERUS.

  Pl. 4.

  Case. Comp. Tablet. Specimen.
   =J=   _a_      6      1-46
                  7      1- 3
                  8      1

There are among the fossils of the Cambridge Greensand at least two
well-marked _types_ of Pterodactyle humerus, readily recognised by the
forms of the proximal and of the distal ends, and by the positions of
the pneumatic foramina. In the group having the ulnar ridge developed
the pneumatic foramen is on the posterior aspect of the bone[O] under
the ulnar ridge, as in birds; but in some of the small Pterodactyles
the foramen is on the anterior surface, and on its radial side. This
latter kind of humerus has the distal end more or less divided into
three convex surfaces, while the radial crest is enormously developed
and terminates in a smooth oblong flattened surface nearly as large
as the proximal articular surface, and looking anteriorly. The distal
articular surfaces are not as in birds parallel to that of the proximal
end, though they agree with those of birds in being at right angles
to the radial crest; this ridge in Pterodactyles being directed much
further outward and backward than in birds.

[Footnote O: Professor Owen states (p. 16, 3d Supt.) that the foramen
is palmar. Fig. 15. T. III. 2d Supt. shows it to be anconal.]

The largest forms of Pterodactyle all have the distal articular surface
flatter, and the proximal articulation less bent back so as to look
more upwards. No specimen of this kind of humerus has occurred with the
radial crest preserved; but it is apparently carried farther down the
shaft and not so far forward as in the other group. This latter kind
of bone is shown by Prof. Owen in T. III. figs. 1, 2, 3rd Sup. Cret.
Reptiles; the former kind has been illustrated in figure 5 of the same
plate.

Some of the most gigantic Pterodactyles appear to have had the
limb-bones as solid as those of crocodiles, and unpermeated by air;
and there is no evidence that the high Avian characteristics of most
of these Greensand fossils also pertained to all the previously known
types from the lower secondary rocks.

The osteological series comprises 46 specimens. No. 30 is a nearly
perfect right humerus. Nos. 1, 2, 5, 6, 7, 8, 9, 11, 18, 22, 23, 25, 39
are examples of the proximal ends of left humeri. Nos. 3, 4, 10, 12,
13, 14, 15, 16, 17, 19, 24, 26, 27, 28, 38, 40, 41 are examples of the
proximal ends of right humeri. Nos. 20, 21, 32, 33, 34, 35, 37, 42, 44,
45, are examples of the distal ends of left humeri. Nos. 29, 31, 36, 43
and 46 are distal ends of right humeri.

No. 30 shows the entire length of the humerus to be 2-1/2 inches. It
has a nearly circular shaft with a diameter of a little more than a
quarter of an inch, being more slender than the corresponding bone
of Pt. suevicus, which has the same length. The _proximal_ articular
surface is crescentic, the anterior concavity corresponding with
the concave anterior aspect of the proximal end, while the convex
border corresponds to the convex posterior side of the bone, which
it overhangs: it is worn, but appears to measure half an inch from
the radial to the ulnar side. The ulnar ridge (which is worn) has
not extended more than a quarter of an inch beyond the articular
surface. The thin bird-like radial crest, arising rather more distally
than the ulnar ridge, is flat on its posterior surface, and extends
anteriorly for a distance nearly half as far again as the length of
the proximal articular surface of the humerus. On the proximal third
of the posterior face are two contiguous long narrow oblique muscular
insertions. The proximal ends Nos. 22, 23, 24, 25 are examples of this
kind of bone, having the pneumatic foramen radially situated on the
anterior aspect near to the articular surface, as may be seen in No.
24. No. 25 shows the termination of the radial crest in an oblique
oblong smooth surface, slightly convex in length and breadth, directed
distally towards the ulnar side.

No. 6, 7, 13, 27, are examples of another kind of proximal end,
where the pneumatic foramen is an oval hole on the ulnar side of the
posterior sur&ce. The radial crest arises more distally, and the ulnar
ridge more proximally, than in the small species, like No. 30.

Nos. 4, 11, 14, 16 are examples of other species with the foramen
placed as in the last group, only less near to the proximal end, while
it enters obliquely, being directed distally from the broad concave
area proximal to it. The largest proximal ends known, such as No. 2,
which though very imperfect measures 2-3/4 inches over what remains of
the articular surface, appear to conform to this latter type.

_Distally_ the humerus No. 30 enlarges, widening rapidly on the radial
side, which is bordered near the distal end by a sharp ridge showing
a muscular attachment, while the ulnar side is rounded and rather
inflated. The articular surface looks downward and in the direction
of the radial process. There is a mesial concavity on the radial side
which is bordered on the right and on the left by a prominent rounded
condyle, and behind by a condyloid convexity. On that side which in
conformity with the nomenclature applied to birds' bones, has here been
named the ulnar side, the ulnar and mesial condyles are impressed with
a flattened slightly concave sub-rhomboid area, which looks downward,
backward, and towards the ulnar side. These characters are not well
seen in No. 30, but may be effectively studied in their specific
variations in Nos. 36, 37, 42, 43, 44, 45, and 46.

Nos. 20, 21, 29, 31, 32, 33, 34, 35, are examples of the distal ends of
humeri of a different type. They are mostly larger than the preceding
group, and correspond in characters with the large proximal ends, but
appear to be separable into two groups, namely those with a pneumatic
foramen on the anterior radial side near to the articular surface,
and those where no pneumatic foramen is seen. Unlike the previously
considered type, the ulnar side is sometimes more inflated than the
radial side.

The mesial condyle in this group appears in every case to be an
epiphysis, which is wanting. The radial condyle becomes a large
flattened slightly convex surface looking downwards, which in some of
the species, as Nos. 21 and 32 (in other respects remarkable species),
shows an approach to a trochlear character on its anterior side. In
Nos. 33, 34 and 35 the mesial anterior concavity becomes flattened and
abuts at an angle against the flattened radial condyle. No. 20 shows
the rhomboid impression on the ulnar side to be more concave and more
ovate. The ulnar condyle remains a smaller but prominent tubercle
directed distally. Nos. 21, 22 and 34 show a ridge developed on the
ulnar side of the shaft like that on the radial side in the other
group, while the radial ridge is not so near to the articular surface.
The largest and smallest distal ends of humeri known, both show the
characters here enumerated. The great distal end of a left humerus,
figured by Prof. Owen, Pl. IV. f. 1, 2, 3 of the 1st Supplement to the
Cretaceous Pterosauria, is of this kind, and though imperfect measures
more than three inches over what remains of the articular surface. In
the small humerus, No. 30, the width over the distal articular surface
is 5/8ths of an inch. If it is assumed that the large bone was no more
than 5 times the length of the small one, the entire length of the
humerus would have been about twelve inches. The smallest humerus, No.
29, measures over the shaft rather more than one eighth of an inch.

The Ornithosaurian humerus has but little in common with that of any
mammal. Most mammals have the proximal head of the bone hemispherical,
and a pit at the distal end for the olecranon process of the ulna,
while there is usually little indication of a radial crest, and the
proximal and distal ends are in the same plane. In the Bat however the
bone is twisted a little so that the slight radial crest looks in the
same direction as the distal end, here also there is no pit for the
olecranon; but the bone is sigmoid and proportionally much longer than
in Pterodactyles. In the horse, hippopotamus, &c., the radial process
becomes more developed but never resembles that of a Pterodactyle.

Among reptiles, the bone may be compared with lizards and crocodiles.
In crocodiles the proximal and distal ends are nearly in the same
plane, the distal end has two condyles, the head is convex from side to
side, and the radial crest is moderately developed and never extends so
far outward or so far proximally as in Pterodactyle. In the Chameleon
the bone is more twisted than in Crocodile, and as in Pterodactyle
the distal end is compressed on the radial side to a sharp margin.
In Iguana, Scink, and Monitor both proximal and distal ends are much
expanded, and the radial process makes no approximation to that of a
Pterodactyle.

The bird humerus does not approximate more closely in form to that
of the Pterodactyle than does the Chameleon humerus, though it has
the cardinal distinction of pneumatic foramina, and these sometimes
corresponding in position in the two groups.

The bird humerus is commonly longer, though in the parrots the
proportions and straightness are not unlike Pterodactyle. In
some respects a nearer resemblance is seen in the raptorial bird
_Gypogeranus serpentarius_, in which the radial process is rather more
developed than in the Crocodile, and extends further proximally though
still much smaller than in Pterodactyle; here too the superior surface
is concave from side to side, and the distal articulation is not unlike
that of some Pterodactyles. But no Pterodactyle has the head of the
humerus convex from the radial to the ulnar sides, and the bird is
distinctive in having the ulnar crest developed on the inferior side
of the head: a faint approximation to a similar development is seen in
Crocodile, but there is no trace of such a process in Pterodactyle. The
distal end is more Bird-like than Lacertian in form, but is twisted to
a greater angle with the proximal end than in birds.

Altogether the bone is distinctive. The points in which it is unlike
birds and reptiles are those in which Birds and Lizards resemble each
other; it would not be easy to say that in form it resembles one group
more than the other. But it is linked with birds by the pneumatic
foramina.


RADIUS AND ULNA.

  Case. Comp. Tablet. Specimen.
   =J=   _a_      9       5- 6
                 10       1-10
                 11       1- 7
                 12       1- 4
                 13       5- 6

Of neither of these bones has a perfect specimen been found. While
fragments of humeri are met with frequently, fragments of these bones
are rare. In accordance with the analogy with birds the Ulna might
be presumed to be the larger bone of the two. But from a study of
German specimens the larger bone is found to be the Radius, which
according to the mammalian plan is placed in front of the ulna. As a
whole, the fore-arm of Ornithosaurians is only to be compared with the
insectivorous mammal _Chrysochloris Capensis_, in which there are also
three bones in the fore-arm,--the third bone like the _Pteroid bone_
in Ornithosaurians, extending about half-way from the carpus to the
humerus, and holding, relatively, a similar position and development to
the fibula in bats.

The pteroid bone articulated with a separate carpal, and was placed
on the side of the arm, adjacent to the radius, which at the distal
end extended in German specimens more inward than the ulna. In
Chrysochloris the third bone appears to be behind the other bones, and
adjacent to the ulna[P].

[Footnote P: See D'Alton and Pander _Chiropteren und Insectivoren_,
Bonn, 1831, pl. 5, Chrysochloris.]

Among neither birds nor reptiles is any comparable modification of
the fore-arm to be found. Then by examining the proximal surface of
the proximal carpal, the characters of the distal end of the Radius
are readily discovered. The proximal carpal shows on the same surface
another articular facets with which however only one fragmentary distal
end of a bone corresponds. That accordingly is identified as the ulna.
Besides these, three other articular ends of bones occur, one of which
fits on to the distal end of the femur. The remaining two are both
large bones, with epiphyses which formed portions of the articular
surfaces, and are usually wanting. One of these bones corresponds in
form with the ulna of a bird, and would fit the facet on the ulnar
side of the distal end of the Pterodactyle humerus. The other bone
is massive with a sub-quadrate articular end, and might well be the
proximal end of the radius. Some specimens are among the largest
fragments of Pterodactyle bone known. The only other bone that either
of these could be is the distal end of the tibia, a bone not yet known,
but probably not unlike that of a bird.


I. Distal End of Ulna.

Four specimens which show articular ends such as the ulna should have,
are mounted together. They are compressed bones with the section of
the fracture elongately oval; and the shaft widens from the fracture
to the articulation without increasing in thickness. The outer surface
is gently convex, becoming concave mesially near the articulation;
the inner surface has the same characters, only the concavity at the
extreme distal end reaches from side to side of the bone. The two short
sides both look outward as well as laterally; one of them flattened so
as to thicken the bone, is concave in vertical outline owing to the
extreme distal end turning suddenly outward; the other side a little
convex, compresses the bone and inflects its inner margin. The longest
specimen measures 1-5/8 inch; 5/8 inch wide at the fracture, and 1-1/8
inch wide at the distal end. The greatest thickness at the distal end
is half an inch, the thickness of the fractured shaft is 5/8 of an inch.

The articular surface appears to have an elongated sub-reniform shape,
the part at the compressed side of the bone being narrower than the
broad ovate part on the thick side of the bone, to the lateral limit
of which it extends, while the narrow part does not extend laterally
nearly so far as the inflected border, which appears to give attachment
to powerful muscles. There is also a strong muscular attachment at the
corresponding diagonal corner of the bone where the outer surface on
its right meets the side of the bone in an elevated ridge.

In its long diameter the articulation is a little convex; transversely
it is very convex in the ovate part, but more flattened in its narrower
continuation. Where widest it measures about 4/10ths of an inch.

Nos. 5 and 6 on another tablet appear to be distal ends of ulna of
another kind of Pterodactyle. They are less compressed, more quadrate
in section, and have the sides more nearly parallel The flattened
side similarly has a concave border, but instead of having its distal
termination developed laterally, has it thickened behind. The opposite
side of the bone which in the other specimens was compressed is here
thick and well rounded, and not at all inflected. There is an absence
of the concavity noticed on the outer surface of the bone in the
compressed specimens. The articular surface is much flatter, and a
little concave in length instead of being convex; as in the other
examples it looks downward. The largest fragment. No. 5, measures 1-3/8
inch long; it is 6/8 inch wide at the fracture, and 4/8 inch thick. The
sub-quadrate distal end is more than an inch long, more than 4/8ths
inch thick on the thick side, and nearly 4/8ths inch thick on the
compressed side.


II. Distal End of Radius.

The best preserved of the 10 specimens here exhibited is 3 inches long,
No. 2. The shaft is oval, flattened on one side; measuring at an inch
from the fractured end 7/10ths of an inch in the least diameter, and
one inch in the wide diameter. It widens distally at first slowly,
then rapidly, till at the articular end its greatest width is two
inches. But while expanding laterally it contracts from side to side,
the more convex side of the two at about an inch from the articular
end, beginning to approximate to the flatter side till the articular
end has a short diameter of less than half an inch.

On the left-hand corner of the convex inner side of the bone is an
elevated flattened disc for muscular attachments, fully half an inch
in diameter, there is a slight muscular attachment interior to this,
nearer the middle of the bone. The left-hand corner of the flattened
outer side of the distal end of the radius is marked by a vertical
ridge bordering a similarly elevated oval muscular attachment. Parallel
to this nearer the middle of the side is a much stronger and acutely
elevated ridge.

The articulation is made up of three distinct parts, all in a straight
line. The portion of bone adjacent to the large muscular disc is
compressed and rounded on the distal end; then first there is a rather
deep circular cup 3/8ths of an inch wide, nearer to the more convex
than to the flatter side of the bone; adjacent to this cup is a convex
ball of about the same size; while the remainder of the articulation
is concave in length, convex from side to side, and looks downward and
a little towards the inner convex side of the bone. The specimens are
arranged so as to display these characters.--The example described is
of nearly the same size as that figured for the humerus in fig. 1, T.
XXIV. of the Cretaceous Reptilia. The less well preserved bone in that
figure exhibits the Ulna in its true position behind the Radius.


III. Proximal End of Ulna.

This bone has much the proportions of the Ulna in birds, the smaller
specimens nearly resembling the ulna of the Heron. The specimen (No.
1) with the shaft best preserved is 2-1/4 inches long, cylindrical at
the fracture, where it measures in diameter 3/16ths of an inch. It
gradually enlarges proximally widening to about 7/10ths of an inch;
near the proximal end it is a little curved, the side which is concave
in length being a little flattened, while there is a lateral elevation
on the opposite side, apparently corresponding to the quill-ridge on
the convex side of the bird-ulna. There is a separate ossification for
the olecranon, which is an irregular sub-oblong bone forming the outer
part of the articulation; it is only preserved in No. 1. Nos. 4, 5 and
6 show the concave transverse groove from which it has come away.

The articular surface looks upward and forward, in which aspect it has
a trapezoidal form. Sometimes, as in No. 2, the great sigmoid area is
divided into two parts by a vertical ridge, the more elevated part
of the articulation on the radial side of the bone being concave,
while the outer part, as in the heron, besides being concave, has its
border on the concave side of the bone produced and rounded. There is
a small triangular elevation on the radial aspect of the proximal end
like that on the corresponding part of the ulna of the heron. On this
aspect the bone is flattened, on the opposite and outward aspect it is
compressed and produced as in the bird. No. 2 measures 1-1/8 inch over
the articular end. The series includes 6 specimens.


IV. Proximal End of Radius.

This bone terminated in an epiphysis which formed part of the articular
surface, and has disappeared from all the 7 specimens mounted. So much
of the articulation as remains does not oppose the idea of its having
been attached to the humerus, while the large size of the example No.
7, which could not have measured less than 2-1/2 inches from side to
side over the articulation, is more in accordance with what is at
present known of the dimensions attained by the distal end of the
humerus than with the size that would be expected in the distal end
of the tibia, which is the only other unknown bone to which these
specimens could be referred.

The longest specimen, No. 3, is 3 inches long; broadly ovate at the
fracture, measuring in the long diameter 1 inch, and in the short
diameter more than 3/4ths of an inch. Nearer the articular end the bone
becomes in section sub-quadrate or rather sub-rhomboid. No. 1 shows
these terminal characters extremely well. On the posterior aspect of
the specimen the surface is divided into two flattened slightly convex
parts by a median vertical well-rounded angular bend. In front the side
is similarly divided into two parts, both of them a little concave
proximally, by a sharp median vertical ridge, which does not reach to
the articulation by a varying distance, never so long as the bone is
wide. The ridge terminates in, and is pierced by, a vertical groove
apparently for a nutritive vessel. Where the anterior and posterior
aspects of the bone converge laterally the sides are well rounded.

Only a small part of the articular surface is preserved, looking upward
and a little forward; it terminates the wider of the halves of the
bone laterally and in front. The remainder of the articular surface,
from which the epiphysis has come away, may be divided principally in
the majority of specimens into a posterior flattened median rhomboid
space and an oblong cup-shaped anterior space divided from it by an
elevated ridge. The extreme lateral termination appears to have been a
ball-shaped convexity.

The great length of the fore-arm relatively to the humerus,
characteristic of German Ornithosaurians, from the fragmentary
condition of Cambridge specimens is not seen.

Although the fore-arm resembles Chrysochloris in _plan_ the
resemblance is not close in the details of form. In many Mammals it is
characteristic for the radius to be the principal bone of the fore-arm,
and among Ruminants in which this is especially the case the radius is
altogether in front and the ulna behind as is the position with Birds
and Crocodiles. And among mammals with claws, as in the Lion, Bear,
&c., and in the Chameleon, it is characteristic, for the radius also to
be on the inside of the limb at the distal end, as in Ornithosaurians.
In form, ridges, and muscular attachments (see pl. 3) the distal end of
the radius approximates closely to the Bear and the Lion, and may also
be compared with the Bats and Birds, though with Birds it is a small
bone. From the epiphysis of the proximal end apparently being wanting
it would be difficult to compare closely. But though not like any
particular mammal, it might have pertained to a mammal since it has the
large perforation for the nutritive vessel near to the proximal end as
in the Camel and many of the mammalia.

The ulna of the Pterodactyles is at the proximal end altogether
distinguished from mammals by the slight development of the olecranon,
nor can the distal end, especially in its relation to the carpus, be
paralleled.

Among birds and reptiles the ulna is the large bone, and here a
general resemblance in form to the ulna of Pterodactyles is seen at
the proximal end. It is not compressed from side to side as in the
Crocodile, Iguana, Monitor, &c., but from back to fronts in this
rather resembling Birds than the Chameleon. It however at the distal
end is more crocodilian.

The fore-arm in plan is mammalian. The Pteroid bone is mammalian, the
Radius is mammalian and avian; the Ulna is avian, and crocodilian in
form, but mammalian in proportion. The pneumatic foramen of the ulna is
peculiarly avian.


  CARPUS.

  Pl. 5.

  Case. Comp. Tablet. Specimen.
   =J=   _b_   1     1-13
               2     1-18
               3     1- 4
               4     1- 8

The pterodactyle wrist is made up of three bones, arranged as a
proximal carpal, a distal carpal, and a lateral carpal. Two of them
are figured by Professor Owen, who regarded the distal carpal of
this description as the scapho-cuneiform; while A very imperfect
example of the proximal carpal is named the unciform: neither of these
determinations, the reverse of those which follow, were given as more
than probable guesses.


I. Proximal Carpal.

No. 10 shows the proximal surface well; portions of it are seen in
Nos. 4, 5, 6, 8, 9, 11, and 12. The distal surface is best exhibited
in No. 1; portions of it are shown in Nos. 2, 3, 5, 7, 8. No. 13 is an
impression taken from the proximal sur&ce of a distal carpal to show
its correspondence with distal surface of the proximal carpal. The
bone is proximally of an irregular oblong form, being five sided, and
much broader towards the inner end than towards the outer end. The two
ends are sub-parallel, and rather obliquely connected on one side by
a nearly straight border more than twice as long as the shorter end.
The other limits of the sub-parallel ends are connected by two concave
borders meeting in a well rounded convexity, which is near to the
broader inner end.

The proximal surface of the bone is flattened, and may be divided into
a sub-rhomboid space, adjacent to the shorter of the sub-parallel ends,
which is moderately concave in the long axis of the bone and slightly
convex transversely, and an oblong space adjacent to the longer of
the two ends. This is separated from the sub-rhomboid space, toward
the straight side of the bone, by an elevated ridge sub-parallel
with the ends. It is directed towards the convexity on the opposite
side, in which the long and short concave parts meet, but after half
crossing the bone it becomes forked in a U shape, and less elevated;
the smooth unarticular included space shows an oval pneumatic foramen,
which varies in size with the different species. The region between
this Y-shaped ridge and the longer of the two ends, is sub-reniform,
slightly concave in its long diameter, and deeply concave in the short
diameter, exactly corresponding in form with the articular surface
already described as the distal end of the ulna. Also parallel with
the long end of the bone are marks of an articular surface exactly
corresponding with those described as the distal end of the radius;
that is, at the convex angle of the angulated side is placed a
hemispherical boss,' interior to which is a hemispherical concavity,
and extending toward the straight side is the oblique smooth border
of the sub-rhomboid area described. There still remains a space to be
accounted for. This consists of a sub-quadrate area forming the corner
of the bone made by the concave side and the shorter outer end; it is
made up of an inner concave part separated from the radial articulation
by a ridge, and an outer convex part constituting the shorter end of
the bone.

This carpal is moderately compressed from the proximal to the distal
side, except towards the shorter end of the bone, being there prolonged
distally into a wedge-shaped process, showing at its termination marks
of a powerful muscular attachment.

The outer lateral surface is of variable antero-posterior extent.

The distal articular surface is placed entirely toward the narrow
end of the bone, leaving at the proximal end a large smooth rhomboid
unarticular area, of which every side is a little concave: it connects
obliquely the proximal with the distal articular surfaces. The distal
articular area is divided by a diagonal ridge into a long oblong area
of which the inner and outer sides are sub-parallel and the ends
rounded: it is slightly concave in length as well as transversely, and
is slightly twisted like the flukes of a screw. Adjacent to this region
laterally is the other and sub-triangular part of the articulation.
The broad end of the triangle is toward the broad end of the bone; it
is concave in length and flattened transversely. The two parts of the
articulation are inclined to each other at a large angle, both looking
downward and outward, but on opposite sides of the bone.


II. Distal Carpal.

The tablets of this bone comprise 22 specimens. Nos. 2, 3, 4, 5, 6,
8, 9, 10, 15, 16, 19 and 22 are so mounted as to exhibit the proximal
surface. Nos. 7, 11, 12, 13, 14, 15, 16, 20 and 21 show the distal
surface of the bone. No. 17 is a cast from the distal sur&ce of a
proximal carpal for comparison with the proximal surface of the distal
carpal. No. 16 is a cast from the proximal end of the wing-metacarpal
for comparison with the distal surface of the distal carpal. No. 20
is a distal carpal of unusual type, 19 is a cast from its proximal
surface, and 21 is a cast from the distal surface of the same specimen.

The proximal aspect of this bone is rather narrower than the distal
aspect; each is sub-triangular in outline, the sides being convexly
curved. In the long axis from the apex on the inside to the short
outer[Q] side the bone is convex proximally with an oblique transverse
depression; in the short axis, that is, between the two longer sides,
the middle of the bone is hollow, but the oblique transverse depression
makes both sides of the hollow convex,--so that excepting the smooth
unarticular triangular area adjacent to the apex, the sub-quadrate
articular surface is shaped somewhat like two cones put side by side
in such manner that the apex of each touches the base of the other:
the apex of that cone which should touch the short side or base of
the triangle formed by the bone, is truncated by a depression which
exhibits an oval pneumatic foramen. Towards the apex, on the same side
as the pneumatic foramen, the margin of the bone is rounded for a small
terminal oval articulation which looks outward and upward.

[Footnote Q: Outer and inner are here used in accordance with the usual
interpretation, and the better to compare with birds.]

The lateral aspects of the bone are at right angles to the proximal and
distal surfaces. They are smooth, a little concave in antero-posterior
extent, and convex in the opposite direction. That one on to which
the marginal articular surface impinges is except for that surface
sub-quadrate in outline; the opposite side has a slightly crescentic
form, the flattened outline being distal. They show several small
foramina.

The distal aspect of the bone is comparatively flat. The distal surface
consists of a smooth unarticular part adjacent to the apex, rather
smaller than the corresponding area on the proximal aspect of the bone.
Between this part and the sub-crescentic articular surface, which
occupies the remainder of the distal area, is a large circular pit,
furthest removed from the side of the bone which forms the sub-apical
marginal articulation. The pit on the apical side shows several small
foramina; on the outer side of the bone the roughened articular
surface extends down the pit side. The articulation is flattened from
side to side of the bone. Its outer margin is slightly prominent, and
the margin of the pit is slightly convex and prominent, so that the
intervening articular surface in the direction between these limits
is concave. It is commonly divided into two parts by a median band
limiting a depressed half, which is in a slightly different plane
from the other half of the articulation. Where the depressed part
terminates towards the marginal articulation, which does not extend
so far distally, there is between the two a small step-like roughened
articular portion.

The large crescentic articulation described gave attachment to the
wing-metacarpal bone; if there was a second metacarpal terminating
in a claw, it must have been attached to the small articulation last
referred to. In No. 20 the pit is extremely small, the impressed part
of the articulation is small and deeply sunk, while the apicular
articulation is widened and shortened so as to make the outline of the
bone quadrate.


III. Lateral Carpal.

The tablet exhibits eight examples of a bone which at its distal end is
attached to the marginal apicular articulation of the distal carpal,
thence extending proximally, and terminating in an articular facet for
the third bone of the fore-arm, so as to overlap laterally both of the
other carpals. The bone is compressed, is three times as wide as thick,
and in outline sub-quadrate with a distal talon. On the inner side it
is flat, and on the outer side above the talon it is concave vertically
and convex transversely in such way that the side of the bone to which
the distal articulation is adjacent is thicker than the other side,
and sometimes bent at a sharp angle. The talon on the inner aspect of
the bone is flat and continuous with the quadrate side, but on the
outer aspect it is separated from the side by an elevated transverse
thickening, distally to which the bone is compressed, and rounded into
the adjacent parts. The talon extends over more than half of the distal
end of the bone, and constitutes with the remainder of the distal end,
the distal articulation, which is flat from front to back, and concave
from side to base. The proximal articulation is cupped and extends over
the whole proximal surface; it is at right angles with the sides of the
bone. Both the inner and outer sides exhibit small pneumatic foramina.
No. 8 differs from the other specimens in its sub-triangular lateral
outline, and general less complex modifications.

The Carpus of the Cambridge Ornithosaurians at first sight is not
easily compared with that of Birds; Birds having but one bone between
the radius and the metacarpus. But that one bone in the Ostrich, for
instance, is not unlike in form to the proximal carpal of Pterodactyle;
while the proximal end of the metacarpus presents so close an analogy
with the distal carpal of the Pterodactyle, that even were it not
easily demonstrated that the bone in Birds commonly called the
metacarpus is a carpo-metacarpus[R], it would be strong evidence for
such a determination. In Birds there is a small lateral bone between
the ulna and carpo-metacarpus which is evidently homologous with the
lateral carpal of our Pterodactyles, and so, since this lateral carpal
of the Ostrich is the pisiform bone, it results that the lateral
carpal of Pterodactyle is the pisiform bone also. From this follows a
conclusion of the first importance in the interpretation of the hand.
The fine hair-like metacarpals of the Pterodactyle are on the side
towards the pisiform bone, while the great wing-metacarpal is on the
side towards the index finger.

[Footnote R: They separate without difficulty in the Chicken.]

In Birds the rudimentary thumb (or second finger, according to Owen)
has no connection with the carpus. In the Penguin, _Aptenodytes
Patagonica_, it has disappeared altogether, and there then remain two
fingers of which the outer one (seen from the front as we have placed
our animal) is the larger, and has the greatest number of phalanges,
precisely as in Ornithosaurians. Moreover the wing-metacarpal, in the
Penguin especially, is seen to unite with the carpus directly under the
radius, as is the case with the Cambridge Ornithosaurians. Hence it
follows that in Pterodactyles the thumb is not developed, and that the
wing-finger is not the little finger, but the index finger, precisely
as in Birds. If Goldfuss gave a reverse arrangement it was because the
hand in his specimen, as is proved by the claws, was upside down. In
the immature state the distal carpal of Pterodactyle appears to have
been composite.

Notwithstanding the opinions of eminent German philosophers to
the contrary no reptile has a carpus comparable to that of the
Pterodactyle. If some of them have two rows of bones and a pisiform
bone, so have mammals, and the mammalian arrangement is not more like
the Ornithosauria than is that in Reptiles.


  METACARPAL BONE.

  Pl. 6.

  Case. Comp. Tablet. Specimen.
   =J=   _b_     5      1-3

The illustrations of this bone comprise 31 specimens. Nos. 1 to 15
are examples of the proximal end, and Nos. 16 to 31 show the distal
trochlear end of the bone. No. 1, which is nearly entire, gives the
form and proportions of the wing-metacarpal in one species, but a
knowledge of its variableness in German forms would guard against an
assumption that all the other Greensand species were to be restored
on the plan of this example. It is 3-5/8 inches long, to which
three-eighths of an inch may be added for the distal articulation,
making the length up to 4 inches. The proximal end is not well
preserved, but in its wide measurement is 5/8ths of an inch; the distal
end in the same measurement is about 3/8ths of an inch. A large example
from the Chalk, in the Museum of C. Moore Esq. of Bath, shows the bone
more attenuated distally. No. 1 is compressed so as to be oblong in
section at the proximal end, and ovate in the middle of the shaft,
which is slightly smaller than the distal end. One of the lateral
outlines is straight; the other is concave. The bone is straight. In
No. 30 the shaft where thickest measures less than 1/4 of an inch,
becoming nearly circular in section. The shaft of No. 31 measures
nearly an inch in width at its distal end, rather more than half an
inch in thickness. No. 10 is 1-1/2 inch wide at the proximal end and
7/8ths of an inch thick. No. 9 would not have measured less when
perfect than 2-1/2 inches over the proximal end, so that if it had the
proportions of No. 1 it would have measured when entire not less than
16 inches in length.

The Proximal End.

The proximal end has never been figured. Prof. Owen's figure pl. IV.
fig, 4-5, First Supt. Cret. Rep. is probably part of a jaw, and not
the wing-metacarpal. The articular surface is oblong with one corner
rounded off so that the adjacent long and short sides become confluent
on the exterior surface of the bone.

In the middle of the flat inside margin and extending proximally is
a semi-cylindrical process, which is prolonged a short distance down
the side of the bone as an elevated ridge. On the flattened articular
end this process is bordered by a semicircular furrow which extends
half-way across the bone, outside of which is a slightly convex
semicircular band which extends to the outer margin of the bone,
except towards the short side opposite to that one which rounds into
the outer side, where there appears to be a narrow unarticular area.
On the inside of the bone where the two ends of the semicircular
proximal furrow terminate are two deep grooves which extend a short
distance distally; they are both limited by inward extensions of the
short sides of the bone, that crest being most developed in height and
length which is toward the flattened short side. The outline which
these modifications give to the inner side of the proximal surface
is intermediate in form between the letters S and [sideways M].


The Distal End.

The distal end has been figured by Prof. Owen in the British Fossil
Mammals, p. 545; in Dixon's Geology of Sussex, Pl. XXIX. fig. 12; Cret.
Reptiles, Pl. XXXII. figs. 4 and 5, First Supt. Pl. IV, fig. 9-11, and
other places, and fully described. It closely resembles the distal end
of a bird's tibia; and consists of a pulley-shaped end set obliquely
on to the compressed shaft, which just above the junction is reniform
in section, owing to the development of _a median rounded ridge_ on
the same inner side of the bone which bears the median ridge at the
proximal end, while on the opposite side there is a corresponding
_median depression_ which does not extend far proximally. In this
depression is an oval pneumatic foramen; on the right of the median
ridge of the other side, but placed more distally, is another pneumatic
foramen. The median ridge has sometimes a slight furrow on each side.
It terminates proximally in strong muscular insertions, which extend
round the right side of the bone; and distally, becoming more elevated
and rounded, it curves obliquely to the rights and forming one of the
sides of the pulley, passes round the base as three quarters of a
spiral, the termination extending laterally beyond the shaft. On this
side of the bone, distal to the median depression, arises another ridge
strong and well rounded, which is directed to the right, similarly
passes round the base as a spiral, and forms the other side of the
pulley. It is not so prominent as the border previously described.
While the spirals approximate at their origin, they become widely
separated at the base, making the articulation wider than the shaft. In
No. 31 the three inches of the shaft which remain show both pairs of
its sides sub-parallel; the widest measures nearly an inch; the base of
the articulation is less than a quarter of an inch wider.

Limited to the base, between the two outer ridges of the pulley, is
a short median ridge slightly developed; so as to flatten the middle
of the concavity between the ridges, and divide it into two grooves.
The degree to which the middle ridge is developed varies in different
species. In No. 30, the smallest pterodactyle, remarkable for a long
wing-metacarpal bone, it is not to be detected. The exterior sides of
the trochlear articulation are broad, flattened, and a little concave.

There is some variation in the way in which the shaft is set on the
trochlear end. It being often in the middle, but not unfrequently
inclined more to one side than to the other.

The metacarpus finds no close parallel among living animals. The
thread-like metacarpal bones suggest the condition of the hind-foot
in the Kangaroo. The predominant metacarpal suggests the ruminants.
But the nearest approximation is found among birds where the bone
for the middle finger is large and the bone for the third finger is
slender. This may be observed (among other examples) in the Penguin
and the Swan. But here the parallel ends. The proximal end in Birds,
we have already seen to be hidden by the anchylosed distal row of the
carpus, and the distal end though often convex from side to side never
presents the trochlear joint of the Pterodactyle. Consequently so far
as regards the form of the articular ends the resemblance is closer
with Reptiles and clawed Mammals than with Birds. In Birds the small
metacarpal is usually of similar length with the large one as is the
case with Pterodactyles.


  FIRST PHALANGE.

  Pl. 7.

  Case. Comp. Tablet. Specimen.
   =J=   _b_     6      1-10

No perfect specimen of the first phalange has been found in the
Cambridge Greensand. Ten bones are mounted to illustrate it, all of
them less perfect than others in the series of associated bones. No.
1 shows the heel of the proximal end; Nos. 9 and 10 are portions of
the proximal articulation from which the epiphysis which forms the
articular heel-part seen in No. 1 has come away. Nos. 2 to 8 are the
distal articular ends of first phalanges. It is improbable that any of
them belong to the second phalange, since they agree in form, and show
muscular attachments which correspond.

Prof. Owen has figured the shaft of a fine example of this bone in
Dixon's Geology of Sussex, Pl. XXXIX. fig. 11. A good proximal end is
shown in Pl. XXXII. fig. 2, of Prof. Owen's monograph of the Cretaceous
Reptilia, but the figure appears to have been previously given in Pl.
XXIV. fig. 2 of the same monograph. By far the grandest specimens are
drawn in Pl. XXX. Prof. Owen names these wing bones. In the "Literature
of English Pterodactyles" the loss of the proximal epiphysis from the
specimen represented in Prof Owen's fig. 1 and 2 led me to interpret
the bone as an ulna. Figs. 1 to 4 represent the proximal ends and
greater portions of the shafts of first phalanges. The lower bone
in fig. 5 is neither radius nor ulna, as stated in the text of the
Cretaceous Reptilia, but the shaft and distal end of a first phalange;
the upper bone being the second phalange.

The Proximal End.

The straight shaft throughout its length is triangular in section. One
side of the bone is gently convex; this may be named for convenience
the outside. The two parts which make up the other side are inclined,
and have the angle in which they meet rounded; one part looks upward
and inward, the other downward and inward. Towards the proximal end the
bone widens and thickens, and the moiety of the inner side which is
away from the heel becomes cleft, and has the sides of the depression
rounded to form a large pneumatic foramen. The articular surface looks
upward and a little outward on the side of the pneumatic foramen.
It consists of two semicircular concave grooves, separated by an
intervening low convexity. The outer of these grooves extends from the
margin of the extreme proximal point of the heel to the widest point
of the bone; the other groove more deeply concave, is a third shorter,
extending from inside the pneumatic foramen to the heel. Here both
grooves converge, terminating in a point, exterior to which a little
distally is a hemispherical mammilate eminence. On the distal side of
the eminence there is a depression so as to make the angle behind the
heel almost hemispherically rounded. This articulation fits on to the
distal articulation of the wing-metacarpal.

When the proximal epiphysis forming the heel comes away, it leaves a
large sub-circular pit with a depressed narrow border.

Distal End.

On nearing the distal end, the angle of the inner side of the shaft
becomes more depressed; and the articulation becomes an elongated oval,
slightly convex transversely and convex in length so as to extend
distally in a curve in such way that the articulation looks downward
and outward from an aspect of the bone exactly opposite to the aspect
from which the proximal articulation looks upward and inward. Hence
the two articular surfaces are sub-parallel; but the distal one at
its distal termination is bent inward, so as to make the adjacent
lateral outline of the bone concave on the inside at its termination.
The articulation does not cover the most proximal part of the distal
surface.


  SECOND PHALANGE.

  Pl. 7.

  Case. Comp. Tablet. Specimen.
   =J=   _b_     7      1-14

On this tablet are mounted 14 specimens. Nos. 1 to 9 are examples of
the proximal end of the second phalange. If there were more than two
phalanges, of which there is no osteological evidence, it is possible
that proximal ends of succeeding phalanges may be included with these.
They all however resemble each, other so closely as to lend no support
to such a supposition. Nos. ?10 to ?14 have been mounted with the
proximal ends because they appear to be portions of the middle of the
shaft of the second phalange; they indicate a rapid distal attenuation,
favouring the idea of there being but two phalanges.

The proximal end of the shaft has the outer side flattened, rarely
concave, commonly slightly convex; the inner side being much more
inflated, and not dissimilar in form to the inner side of the first
phalange. Proximally the bone widens and one lateral outline extends
outward in a curve, on the inner side of which, under the proximal
articulation, is placed the pneumatic foramen. The elongated oval
articular surface is concave from side to side and concave in length;
it does not extend in length so far as the straight side outline,
exterior to it being a crescentic flattened or convex area. The distal
end attenuates more rapidly in some specimens than others, and appears
in Nos. 11, 12, and 14 eventually to become cylindrical; but none of
the specimens show its distal termination.

The phalanges of the wing-finger attain a grand development in length
which is not paralleled in Birds, nor surpassed in Bats. In the Ostrich
there are three phalanges in the wing-finger, while in Ornithopterus
there are two joints, and in other German Pterodactyles four joints.
The terminal joint in the Ostrich is a claw, but in Pterodactyle the
terminal joint appears to be unarmed as in ordinary birds. The form of
the bones in being compressed from side to side is more bird-like than
bat-like. But the claws in their compression from side to side are more
like the bat than the bird.


  DISTAL END OF METACARPAL

  or Metatarsal Bones.

  Pl. 6.

  Case. Comp. Tablet. Specimen.
   =J=   _b_     7      1-14

Sub-cylindrical bones, apparently elongated, and a little compressed
obliquely, terminating distally in a slightly expanded trochlear
articulation. Some of them show on one side marks of an osseous
adhesion: this has led to their being regarded as claw metacarpals
rather than as the distal ends of tibiæ. But on the supposition of
their being claw metacarpals, they are as compared with the same bones
in _Pt. Suevicus_, out of all proportion large, since wing-metacarpals
from the Cambridge Greensand would not as a rule have a diameter
more than twice that of these bones. The trochlear articulation is
smaller in proportion to the shaft than in the wing-metacarpal, and
usually shows a pit at the side and grooves above for ligaments; the
mesial pulley groove is shallow and broad. Seven specimens are mounted
in illustration, of which No. 3 may be regarded as doubtful. It is
possible that they may be metatarsals.


  CLAW PHALANGE.

  Pl. 8.

  Case. Comp. Tablet. Specimen.
   =J=   _b_     8      1-3

These three sub-triangular bones, which supported the claws, are much
compressed from side to side, and consequently deep. The superior
outline is convex from front to back and rounded from side to side. The
inferior outline is concave from front to back, sometimes narrower,
sometimes broader than the upper part of the bone, while the inferior
aspect is always more flattened than the superior aspect. On each side
on the lower half of the bone is a deep groove. The articular end is
divided into an upper articular part, which extends as far down as the
lateral groove and a lower non-articular part with ligament markings.
The articulation is concave from above downward, and is divided into
two lateral parts by a mesial vertical ridge. The articular end is
about half as deep as the bone is long.


  Pelvic Girdle and Hind Limb.

  OS INNOMINATUM.

  Pl. 8.

  Case. Comp. Tablet. Specimen.
   =J=   _b_    10      1-9

Nine specimens are mounted in illustration of the pelvic girdle: Nos.
1, 3, 4, 5 and 6 show the acetabular or femoral aspects. The right os
innominatum is exemplified by Nos. 1, 4 and 5; the left by Nos. 3 and
6. No. 2 shows the sacral aspect of a left ischium, and its attachments
with the pubis and ilium. No. 8 is the sacral aspect of a left os
pubis. No. 9 is the femoral aspect of a right OS pubis. None of the
specimens are sufficiently complete to give the form of any of the
bones. The only known example of an entire or nearly entire pelvis at
all comparable in form, is seen in the original specimen of Dimorphodon
macronyx figured by Buckland, _Trans. Geol. Soc._ Ser. 2. vol. III. p.
217. In nearly all the fossils from the Cambridge Greensand the bones
of the pelvis are anchylosed together.

The ossa innominata have been determined as right and left on the
supposition that the pelvis of the Dimorphodon is in situ, and from the
general correspondence of the form of the constituent elements with
elements of the pelvis in the lower mammals, reptiles, and birds.

Each os innominatum shows a hemispherical acetabulum which is slightly
elongated in antero-posterior extent In the Dimorphodon the bone which
is superior to the cup, that is to say, which extends dorsally along
the sacral vertebræ is prolonged anteriorly as a strong narrow straight
style, the base of which is seen in the parts marked _Ilium_ in Nos.
1 and 6. A more perfect example may be studied in a pelvis from the
Cambridge Greensand preserved in the collection of the Geological
survey. Posterior to the acetabulum a similar but stronger bony style
extends for more than the length of the acetabulum, curving slightly
downward at its posterior part. The dorsal outline of this portion of
the bone is slightly concave. The posterior horn like the anterior
horn forms part of the ilium which constitutes the upper half of the
acetabular cup. The os innominatum contracts in antero-posterior
extent below the acetabulum, and immediately widens again in a thin
concave bony expansion. The anterior or pubic outline is comparatively
straight, and at right angles with the ilium; the posterior or ischiac
outline is deeply cupped where the ischium unites with the ilium, and
becoming straight extends backward at a considerable angle. The ischium
contributes less to the pelvic cup than either the ilium or pubis;
it is flat in front and convex on the visceral side, rounding into
the narrow flattened posterior side. The pubis is separated from the
ischium by a suture extending vertically through the obturator foramen.
The obturator foramen [seen in No. 9] is small and oval, less than half
the diameter of the acetabulum, situated below its ventral border. It
passes obliquely downward and a little forward, and its opening makes
the exterior aspect of the pubis concave; the visceral aspect of the
pubis is convex from side to side like the ischium. The sacral aspect
of so much of the os innominatum as is seen, is concave from the dorsal
to the ventral margins, and is cupped behind and below the acetabulum,
the surface being rough. Among reptiles the ilium is chiefly behind
the acetabulum, in mammals it is chiefly in front. In the over-lapping
group, Aves, it extends both ways. Among the Amphibia the ilium is
chiefly anterior to the acetabulum. In Crocodiles it has a slight
extension both ways, in Dinosaurs the extensions are more marked and
the whole arrangement approximates to birds. But among animals which
have been affiliated with reptiles the Dicynodonts are the only order
in which there is a pelvis so mammalian and massive. If the ilium of
the Monotreme genus Echidna had a posterior extension, the pelvis would
be altogether comparable with the pelvis of this Pterodactyle, and
would differ chiefly in the larger obturator foramen, the perforated
acetabulum and the unanchylosed condition of the pelvic elements. The
pelvis of Apteryx does not make any near approximation.

Moreover specimens Nos. 3 and 4 show on the anterior pubic border,
about the base of the acetabulum, a slight pit or roughness to
which something has been attached, and in the original specimen of
Dimorphodon associated with the pelvis are two triangular bones which
recall something of the form of the prepubic bones of Echidna. Most
German Pterodactyles show on the OS pubis an enormous prepubic bone.
In Iguana the pubis forms at its anterior border, a sharp angular
process. In Chelydra the process is long and narrower, and arises
from the middle of the border. In Echidna this prepubic process has
become a distinct prepubic bone and is more elongated. Unlike the
marsupial bones it is attached to the pubis by a wide base. The
anterior pubic roughness of Cambridge specimens, and the loose bones
of the Dimorphodon, &c. indicate the existence of structures in the
Ornithosauria homologous with the prepubic bones of the Ornithodelphia.

So far as it is comparable with living animals, the ilium is altogether
avian, differing in being narrower; and the pubis and ischium are
mammalian.

The upper anterior corner is the most elevated part of the acetabular
border, as in the great Auk and some birds of vertical position of
body, and many mammals.


  FEMUR.

  Pl. 8.

  Case. Comp. Tablet. Specimen.
   =J=   _b_    11      1-16

Twenty-six specimens are mounted to illustrate the Femur. 10 are
proximal ends; 16 distal ends. But in the series illustrative of
species is an entire specimen of a right Femur 4 inches long. Fragments
Nos. 3 and 12 show proximal and distal ends twice as large, but most of
the examples are about the size of the entire femur.

It is a straight sub-cylindrical bone, flattened in front, a little
compressed from front to back distally, and (in one type) compressed
proximally from side to side behind. The distal articulation has a
broad shallow channel passing down from the front and imperfectly
separating two condyloid parts, which extend a little backward and
are divided behind. The outer condyle extends a little outward, and
so gives the outer side of the bone at the distal end an oblique
compressed aspect like that which prevails among birds and many
mammals. Proximally the shaft contracts suddenly and is produced
upward, forward, and inward as a rounded neck, as long as in the femur
of any mammalian carnivore, which expands rapidly at the end to form
the hemispherical ball, which articulates with the pelvic acetabulum.

No. 1 shows a well-marked pit for the ligamentum teres at the back part
of the ball. At the proximal end of the shaft below the neck is a large
pit for the obturator muscle, and at the outer front angle a great
trochanter. Proximally the bone can only be compared with the mammalian
Carnivora, Quadrumana and Man; distally it is avian and mammalian.

In one genus exemplified by specimens 5-10 the obturator pit is not
developed.

Sometimes the shaft is curved a little convexly, outward and forward.

  TIBIA.

  Pl. 8.

  Case. Comp. Tablet. Specimen.
   =J=   _b_    12      1-11

Eleven specimens are mounted to illustrate the tibia, of which 1 to
9 are regarded as proximal ends; and 10, 11 with less confidence are
regarded as distal ends from which the distal epiphysis has come
away. It is to be anticipated that the distal end of the tibia in
Pterodactyle will when found approximate to the distal end of the tibia
in the bird.

The bone is at the proximal end straight and sub-cylindrical, slowly
enlarging proximally; convex behind, except for an elevated boss some
little way below the proximal articulation for the attachment of
powerful muscles. In front the shaft is a little flattened proximally,
with a mesial groove dividing two prominences which are apparently
homologous with the ridges below the patella in birds. The proximal
articular surface truncates the shaft at right angles except at what
is regarded as the outer front aspect, where it rises into a small
patelloid prominence.

It shows the impressions of two condyles, which correspond in form with
the distal end of the Femur.

Nos. 3 and 6 are regarded as left tibia; Nos. 4, 5, 7, 8, 9 as examples
of right tibia.

No specimen likely to be a fibula has been found. In Dimorphodon and
in German Genera the fibula is Avian in form. The Crocodile offers
some approximation to the Pterodactyle shape in the proximal end of
the Tibia, but the Pterodactyle has Avian characters in addition. Its
straightness and length, ridges on the front and patelloid prominence,
are Avian.

  TARSUS OR TARSO-METATARSUS.

  Pl. 8.

  Case. Comp. Tablet. Specimen.
   =J=   _b_    13       1

This fragment, which may be the distal end of the bone corresponding
to that called in birds the tarsus or tarso-metatarsus, is badly
preserved. Yet so close is its resemblance in form, structure, and
apposition of the constituent bones to what obtains among birds,
that it may probably be identified as the tarsus; while the peculiar
characteristics of Pterodactyle bones which it shows, demonstrate that
it is not from a bird, but from an Ornithosaurian skeleton.

The bones are of paper thinness, and consist of a strong bone behind
which distally appears on the inner side to be compressed and thrown
backward and flattened at the side, exactly like the inner toe in
Natatorial birds. On the front of this strong support, confluent with
it, and confluent together, so that the places of union are only seen
at the distal end and in transverse section, are three bones, together
as wide as the bone on which they rest. It does not appear possible
that the distal articulations could have supported more than three
digits.

This bone, if correctly determined, offers points of affinity
with birds as pronounced and as important as any thing shown by
the extremities, for among reptiles a welding of the (tarsal or)
tarso-metatarsal bones is unknown, and here it is as absolute as in any
bird, and takes a characteristic bird shape. In the Rodent Jerboa the
metatarsus has much the same form as in a bird.

No phalanges have been recognised.


The Vertebral Column.

  ATLAS AND AXIS.

  Pl. 9.

  Case. Comp. Tablet. Specimen.
   =J=   _c_     1      1-15

Fifteen specimens are mounted to exemplify the structures of the
Pterodactyle atlas and axis. Nos. 1, 11, and 2 have already been
figured, and described by Prof Owen, the latter as a section of a
cervical vertebra.

The _atlas_ centrum, a saucer-shaped disk of bone, commonly united more
or less intimately with the centrum of the axis, but sometimes free. It
presents in front a hemispherical cup for the basi-occipital, and is
flattened or slightly convex behind. Its neural arch is seen in Nos.
2, 10, and 12; but the only specimen with the arch entire is in the
museum of James Carter, Esq. The neurapophyses vary in form and size,
but always are small obliquely flattened lamellar bones, which extend
upward and backward to meet the neural arch of the axis, just above the
neural canal, where a thin and small cross piece connects them together.

The distinctive aspect of these bones is given by the neural arch of
the _axis_, which is very much elevated, and is formed by two flattened
sides, which meet in a vertical ridge above the neural canal, and look
forward, outward and upward; extending laterally more and more beyond
the side of the centrum, but not reaching so far back as the posterior
articulation of the centrum. Each side of the neural arch at its middle
part behind is produced into a thick obliquely flattened process,
the under portion of which shows the small posterior zygapophysial
facets, which look downward, outward and backward. The lateral outline
of the part of the neural arch above this process is concave; as is
the lateral outline between it and the centrum. Behind, the neural
arch is concave, and looks a little backward. The neural canal is
stirrup-shaped in front, but is higher and sub-ovate behind. The neural
arch of this, as of all the other vertebræ, except a few dorsals, is
inseparably united to the centrum, without a trace of the line of
union. In the middle of the side of the vertebra, and at what may be
presumed to be the union between the neural arch and the centrum, in a
concavity, is the pneumatic foramen. It is round or oval, and varies
in form and size though not in position. In No. 8 it exhibits the
subdivided reticular structure characteristic of the pneumatic foramina
of birds. In No. 10, which has a short centrum, the pneumatic cavities
are reduced to a few small perforations, no larger than would be made
with fine needles.

The centrum is shorter than in cervical vertebræ, commonly convex
(No. 8) on the visceral surface; often with a slight longitudinal
hypapophysial ridge (Nos. 1; 7; 12) rarely flattened (No. 10). Towards
the hinder part the centrum widens, and becomes concave on the visceral
surface, sending off as do the other cervicals, below the transversely
elongated posterior articulation, a pair of short strong apophyses.

The posterior articulation can only by a modification of the idea
be said to conform to the cup-and-ball plan, for though convex from
above downward and convex from side to side, the elongated transverse
measurement would be three times the depth. On the under side an
impressed transverse line divides the articulation from the concave
part of the centrum below.


  Cervical Vertebræ.

  Pl. 9.

  Case. Comp. Tablet. Specimen.
   =J=   _c_     2      1-43

Forty-three specimens are mounted to exemplify the variations in size
and characters of cervical vertebræ. These for the most part are
specific characters; and between the axis and the first dorsal vertebra
the variations in an individual were slight. [Those nearest to the
back, as in birds, are widest in front, and have the highest neural
arches.] The associated series show commonly four cervical vertebræ
behind the axis, and in two cases apparently five; never more. So that
as seven appears to be the number of true cervical vertebræ in most
if not all of the German Pterodactyles, it may be presumed that the
Cretaceous Ornithosaurians also had this character in common, with
Mammals, and probably as persistent. In Iguana there are 6, in Monitor
7, and in Crocodile 8.

The centrum is united to the neural arch as in birds, without a trace
of suture; sometimes the neural arch is no wider than the centrum,
sometimes it extends over the centrum on each side. Those forms
with a narrow neural arch have the neural spine high, and its sides
look forward as well as outward. The pneumatic foramen is oblique.
An example is figured by Prof. Owen, in the memoir on Pterodactylus
simus, pl. 2, fig. 4. The forms with a wide neural arch have the neural
spine rising from the middle of the dorsal surface, erect and equally
compressed from side to side. The pneumatic foramen is horizontal. An
example is figured in Prof. Owen's memoir on Pt. simus, pl. 2, fig. 1.
These two forms of cervical vertebræ may be regarded as typifying two
genera.

In both forms many characters occur in common, and as the specimens
illustrative of special modifications will be described hereafter,
the following description has been made to embrace the chief
characteristics of these vertebræ in Cretaceous Ornithosaurians.

The inferior aspect of the centrum is oblong (being narrower than
long), or quadrate; when quadrate the additional lateral expansions are
external to the pneumatic foramina, and are formed by the neural arch
and zygapophyses. The centrum proper is a little wider in front than
behind, and the side outlines are concave. The base of the centrum is
flattened, or more or less hollow, or more or less tumid and regularly
convex; in front there is often a mesial ridge, which never reaches
the posterior articulation, and forms a prominent tubercle at the base
of the anterior articulation. At the posterior end the outline of the
centrum is concave, and mesially the bone has a hollow corresponding
to the tubercle in front of the adjacent vertebra; and the part of
the centrum on each side is prolonged slightly into a strong rounded
or flattened tubercle below the side borders of the posterior
articulation; these posterior processes, in vertebræ in situ, fitted,
on each side of the mesial anterior process of the vertebra behind, on
to concavities more or less marked. Analagous processes are developed
in the cervical vertebræ of many birds.

All the Cretaceous Pterodactyles have the articular surfaces of
the centrum transversely oblong, as have some birds. The posterior
articulation is convex from side to side, and convex from above
downward, and appears to extend a little further on this neural than
on the hæmal surface; in outline it is commonly an elongated oval,
but sometimes attends on the upper surface of the inferior lateral
tubercles. The anterior articulation is transversely elongated, concave
in both directions, and sub-triangular in outline; that is to say, the
superior outline is more or less convex, and from its limits to the
mesial tubercle at the base, the inferior outlines are more or less
concave.

The neural canal is sub-circular or ovate in outline, and quite as
large as the neural canal in vertebræ of Dinornis of similar size.

The neural arch like the centrum has commonly a depressed appearance.
It always has a neural spinous process which is directed upward. In
the depressed type the neural surface of the vertebra is in outline
usually sub-quadrate, but concave at each side, and concave in front
and behind; the four corners are the processes which support the
zygapophysial facets, the surface is divided into two lateral parts by
the strong neural spine. These lateral parts are from front to back
flat, or slightly concave, or slightly convex; and from the neural
spine outward they are always concave. The neural spine is commonly
sharp in front and flattened behind. The neural arch is placed well
forward, so that while a third of the neural canal remains uncovered by
it behind, rarely a sixth would be uncovered in front.

The anterior and posterior zygapophyses are commonly connected by a
more or less rounded ridge, undefined above, but well defined below,
since under its posterior part at about the middle of the side of the
centrum is placed the pneumatic foramen.

The anterior zygapophysial processes are separated from the anterior
articular surface of the centrum by a more or less oblique channel.
Towards the base of this channel in many vertebræ may be seen a small
and short flattened antero-posterior perforation corresponding in
position with the usually large perforation for the vertebral artery.
If the passages are to be regarded as having subserved such a function,
it will not be without interest to remark the small relative size of
the cerebellum in these animals; since the vertebral artery conveys the
blood to that region of the brain.

The anterior zygapophyses are strong processes directed forward and
outward, compressed a little from side to side; they are placed at the
outer sides of the anterior articular face of the centrum, and extend
in front of it.

The zygapophysial facet is commonly oval and looks upward and inward
and forward.

The posterior zygapophyses are short and massive, but otherwise
correspond closely with the anterior zygapophyses, only with all the
parts reversed, and except that necessarily they are relatively to the
neural canal a little higher.

A sharp and well defined angular ridge, commencing at the back of the
zygapophysis, is directed inward, and forward, and upward along the
posterior margin of the neural arch to the top of the neural spine. The
posterior aspect of the neural arch is concave from side to side, and
makes a right angle with the superior lateral aspect.

The part of the centrum exposed behind the neural arch is convex above
from side to side.

The pneumatic foramen between the centrum and the neural arch varies
greatly in size; it is oval and longitudinal.

The largest specimens have the centrum 2-1/2 inches long; in the
smallest the centrum measures 5/8ths of an inch in length.

In the second type of cervical vertebra the side of the centrum makes
a right angle with the base, and is separated from it by a sharp angle
as in struthious birds. The side of the centrum is concave, with a
few small pneumatic perforations; and the side of the centrum, which
is high posteriorly, rounds over the oblique ridge connecting the
zygapophyses, into the oblique lateral face of the neural arch. The
anterior zygapophyses are very large and the posterior zygapophyses
small and placed as high as the top of the neural canal.

Every region of the vertebral column displays pneumatic foramina,
situated as in the vertebræ of birds.

The large proportional size of the neck-vertebræ is common to some
birds, and is conspicuous in many mammals, like the Llama. In most
mammals where the vertebræ have a cup-and-ball articulation, the ball
is in front, as it is in the dorsal vertebræ of the penguin, so that
those vertebræ are not comparable with Pterodactyles, although on the
under side of the centrum they similarly give off a mesial process
below the cup, and a lateral process below the ball on each side. The
neural spine in Pterodactyle is commonly more developed than is the
case with long-necked birds or mammals. Reptiles such as Crocodiles and
Lizards have the neural spines of the neck-vertebræ well developed.
Birds differ from Pterodactyles in the peculiar articulation of their
vertebræ. In both the centrum is often depressed, in both it is concave
from side to side in front, and convex from side to side behind, but
in birds it is also convex from above downward in front, and concave
from above downward behind, while the reverse arrangement obtains in
Pterodactyles. A similar condition to that of the bird is seen in
the neck-vertebræ of the Kangaroo, of Man, and several mammals, only
the vertical curves are less marked. Vertebræ concave in front, and
convex behind, and devoid of cervical ribs, are met with among the
Lizards, but neither Monitor nor Iguana offer any parallel to the form
of the cervical vertebræ of Pterodactyle, which is best matched among
Marsupials and Birds. Birds commonly have more vertebræ in the neck
than have Pterodactyles, which in that respect resemble mammals and
some Lizards.


  Dorsal Vertebræ.

  Pl. 10.

  Case. Comp. Tablet. Specimen.
   =J=   _c_     3      1-20

Twenty specimens are mounted to exemplify pectoral and dorsal vertebræ.
Like the cervical vertebræ, they include two types of form, one with
the centrum flat, figured in pl. 2. fig. 20-22 of the memoir on
Pterodactylus Sedgwicki, and regarded by Prof Owen as anterior dorsal;
and the other form with a convex centrum, figured 24-25 of the same
plate of the same memoir, regarded by Prof. Owen as posterior dorsal.
Following the analogy of birds such determination is as well supported
as the similar reference of the two types of cervical vertebræ to
anterior and posterior parts of the neck, but fuller materials compel a
reference of the two types of dorsal vertebræ to two different genera.

  Nos. 1, 3, 6, 7, 8, 9, 10, 14, 15, 19 belong to the flat type. Nos.
  2, 4, 5, 11, 12, 16, 17, 18 exemplify the convex type.

Dorsal vertebræ are rare fossils; and in the associated sets of bones
never more than four dorsal vertebræ are found, rarely more than one.
No specimen of the type with a convex centrum occurs in the associated
sets.

The dorsal vertebræ with convex centra have all lost their neural
arches except No. 2. The form of the centrum is half a cylinder, as
long, or longer than wide, but sometimes depressed, and wider behind
than in front. The exterior surface is smooth, convex from side to
side, and slightly concave from front to back. The neural surface is
mesially excavated. Both anterior and posterior articular surfaces are
semicircular or sub-ovate, being wide from side to side.

The anterior articulation is cupped, concave from the neural to
the hæmal surface, and concave from side to side. The posterior
articulation is convex from the neural to the hæmal surface, in which
direction, it usually shows striations, and from side to side has a
gentle convexity, sometimes so slight as to be nearly flat.

The neural canal is large, ovate, and as high as is the centrum.

The neural arch is strong, compressed from back to front, and placed
as usual on the anterior part of the centrum. In outline it is
sub-rhomboid with the sides concave. There is a strong process on
each side above the neural canal for a rib, and apparently a neural
spine, but all are broken. The transverse processes for the ribs are
directed outward, and a little forward, flattened in front and behind,
the surfaces being sub-parallel, so that in front the neural arch
is concave from side to side. Behind, the neural spine is directed
between the transverse processes so as to over-hang the exposed part
of the superior surface of the centrum. At the points where the neural
spine bends back from the transverse processes are the posterior
zygapophyses, high above the neural canal, and parted from each other
by an interspace as wide as the canal is high. They look downward,
outward, and backward. The lateral surface below the transverse process
is narrow, flattened, bends at a right angle with the posterior
surface, rounds into the anterior surface, is a continuous curve with
the side of the centrum, and is concave from below upward. The superior
surfaces of the neural arch have the sides sub-parallel, they are
each concave from side to side; and these surfaces are excavated for
pneumatic foramina.

Dorsal vertebræ of the type with the centrum flattened closely resemble
cervical vertebræ with the centrum flattened, differing chiefly in the
less length of the centrum. Occasionally (as in No. 3) the neural arch
comes away from the body of the vertebra.

The centrum is very depressed, sub-quadrate, and wider than long;
the base is flat, or slightly concave, with occasionally a slight
longitudinal mesial ridge; the lateral outlines are concave, so that
the bone is pinched in from side to side. The neural surface of the
centrum is flat and parallel with the base, and, as usual, wider behind
than in front, but the centrum is not there so high. The surfaces for
the neural arch are flat, and extend nearly to the base of the centrum
in front, so that they look upward, outward and a little forward.

The articular ends are remarkable for their depressed oblong character,
still preserving the anterior concavity with a small mesial process
below, as in cervical vertebræ, and similar but smaller processes
at the inferior outer angles of the posterior sub-semicylindrical
convexity. The middle third of the anterior cup is made by the
trapezoidal anterior end of the centrum; sometimes the sutures between
it and the neural arch are well marked.

The neural arch is large, commonly with a sub-circular neural canal.
The neural spine is high, compressed so as to have the lateral surfaces
sub-parallel and rounding into each other superiorly; and it has a
less antero-posterior extent than the centrum. At its base behind
it widens rapidly, and forms massive quadrate processes, extending
outward and backward, which on the outside each have a flattened ovate
zygapophysial facet, which also looks downward. Above the facet and
separated from it by a groove is a tubercle. Between the zygapophyses
behind the bone is concave from side to side; the facets are placed
above the neural canal.

The posterior zygapophyses are placed considerably higher than the
anterior zygapophyses, and the part of the neural arch between is
rather constricted from front to back. The neural arch steadily widens
in front down to the base of the anterior zygapophysial processes in
such way that the more or less flattened lateral surface looks outward
and is gently concave from above downward. A ridge commencing at the
tubercle over the posterior zygapophysial facet descends in a curve
forward and downward, to form the posterior border of the anterior
zygapophysial process. This is separated by a groove from the anterior
articular surface, and anterior part of the base of the centrum, and
has the aspect of a compressed part of the neural arch, extending
obliquely downward, and forward, over and beyond the articular surface
of the centrum. The anterior zygapophysial facets are oblong, narrow
from side to side, and long from front to back; they are directed
forward and a little outward, and are flattened, make nearly a right
angle behind with the front of the neural arch, and look upward and
inward. They are sometimes placed as high as the top of the neural
canal, but are commonly lower. Around the neural canal the bone is
conically impressed.

Minute pneumatic foramina are in the usual position, between the
centrum and the neural arch; and sometimes others behind the anterior
zygapophysial process.

The largest specimen known has the centrum nearly an inch and a half
long.

The dorsal vertebræ in Cambridge specimens would appear to make a
nearer approximation in number to birds than to Mammals or Lizards or
Crocodiles, though Chelonians have few vertebræ in the back. Among
Reptiles the form of the vertebra makes some approach to that of the
Monitor, Chameleon and Scink. In most Mammals the dorsal vertebræ have
the centrum convex, though in the lumbar region its visceral surface
often becomes flattened. But though very unlike there is a nearer
resemblance to the lower dorsal vertebræ of a Struthious bird.


  Sacrum.

  Pl. 10.

  Case. Comp. Tablet. Specimen.
   =J=   _c_     4      1-7

Seven specimens are mounted to exemplify the ordinary structures of the
Ornithosaurian sacrum.

Nos. 1 and 2 have the centrum convex, exactly as in the dorsal vertebræ
of the convex type. Nos. 3-7 have the centrum flattened, following in
general features the plan of the dorsal vertebræ with flat centra.

No. 1 is a vertebra from a sacrum, where perfect anchylosis had not
been induced; it has the neural arch well preserved, and shows the
sharp suture which united it to the preceding vertebra.

No. 2 shows two entire vertebræ and part of a third, which have lost
the neural arches but have the centra perfectly anchylosed together.
The middle vertebra measures 5/8 of an inch in length, and at the
suture from side to side measures more. The surface is smooth,
regularly convex from side to side, and gently concave from back
to front. The last vertebra shows the articular vertebral surface;
it is convex in both directions, and oblique, so that a large part
looks upward. The anterior of the three vertebræ is pinched in at the
lower part of the sides of the centrum. No. 1 shows that the neural
surface of the centrum is deeply excavated, making the neural canal
an elongated upright oval. Above the centrum, which forms only the
middle third of the articular surface, the neural arch expands on each
side into a wedge-shaped transverse process, the lower surfaces are
flattened, and continuous with the centrum, while the upper surfaces
are flat and horizontal as in birds and Dinosaurs, and form the
platform from which arises the massive neural spine.

In front the transverse wedge is flattened and compressed, so as
to look forward and outward, and in the middle shows a large ovate
pneumatic foramen. Behind, the wedge is compressed so as to look
backward and downward.

The neural spine is massive and forms rather more than half the height
of the vertebra. It is flattened with a ridge rising near its base in
front and ascending in a concave curve obliquely backward and upward.
The anterior parts approximate a little in front, while the small parts
posterior to the ridge approximate a little behind. The sides of the
neural spine approximate superiorly, and appear to round into each
other.

There is a notch on each side in front at the base of the neural spine,
and another above the central articulation. The neural spines appear to
have been united by suture. It may be instructive to compare the neural
spine just described with the specimens =J=. _c_. 10.

Of the second type or genus No. 4 to 7 all show the anterior cup for
the last lumbar vertebra. No. 3, 5 and 6 all show two entire vertebræ
and part of a third preserved, but no specimen shows the posterior
termination of the sacrum. No. 7 has the articular face of the centrum
very broad, and greatly depressed. In No. 6 it is ovate and has the
neural arch preserved; above a semicircular neural canal it sends
out on each side a short horn-like zygapophysial process. No. 4 is
remarkable for the small size of the circular neural canal, the centrum
when entire measuring an inch from side to side, while the neural canal
only measures 5/16 of an inch. No. 5 is figured by Prof. Owen. No. 4-6
appear to have given off transverse processes from the sides of the
centra. No. 7 appears to widen into transverse processes at the point
of suture between the centra.

In No. 3 the base of the sacrum is flattened, and its sides pinched in,
and concave in outline from back to front. In this hollow are small
pneumatic foramina, and between the hollows the vertebræ widen in the
line of the suture so as to send out strong short transverse processes
or tubercles. Above the hollows are given out the strong horizontal
quadrate pyramidal transverse processes. All their sides are flattened
or a little concave, and the under side displays a large ovate
pneumatic foramen. Each of the four angles of the transverse process
gives off a ridge. The lower ones descend obliquely to the anterior
and posterior intersutural tubercles. The upper two ascend obliquely,
in front and behind, and form rounded ridges on the neural spine. The
neural spine is flattened, moderately compressed from side to side, and
cupped a little over each transverse process. In front the neural spine
is flattened transversely and perpendicular; the transverse processes
are also flattened and a little in advance of the neural spine.

The sacrum in its general aspect is Mammalian. In the Bird the
vertebræ are much more numerous and do not retain their individuality
so well. In Reptiles properly so called, the sacrum never includes more
than two or three vertebræ, and those commonly remain unanchylosed. But
in almost any placental Mammal in which several vertebræ are anchylosed
together, a sacrum similar to that of the Pterodactyle is met with. No
mammalian sacrum, however, is furnished with pneumatic foramina.


  Caudal Vertebræ.

  Pl. 10.

  Case. Comp. Tablet. Specimen.
   =J=   _c_     5      1-13

Thirteen specimens are mounted to exemplify the osteology of caudal
vertebræ. No. 7 has been figured by Prof. Owen in the memoir on
Pterodactylus simus, pl. 2 fig. 13-16. The centrum of the largest
specimens measures one inch and a quarter long, and the vertebra
is half an inch wide from side to side in the middle. The smallest
specimen No. 13 has the centrum 3/4 of an inch long. The vertebræ vary
in proportions, some being much more slender than others. They present
a close approximation in form to the first type of cervical vertebræ,
differing chiefly in being more elongated.

They are elongated bones constricted in the middle, so that the
outlines of the sides seen from above or below are gently concave;
the outline of the anterior end is sub-rhomboid, the outline of the
posterior end is sub-pentagonal, as would be a transverse section of
the vertebra. The long outlines of the base of the centrum and of the
top of the neural arch are sub-parallel.

The two sides of the upper surface of the neural arch are smooth,
flattened, a little concave from back to front; they are inclined to
each other pent-house wise at about a right angle, and are separated
throughout their length by a narrow slightly elevated neural spine.
Behind, the neural arch is truncated transversely so as to expose
the posterior neural surface of the centrum, which is convex from
side to side. The outermost lateral angles of the neural arch are the
posterior zygapophysial processes, short and strong above the centrum,
with a tubercle on the upper surface, and showing the sub-circular
zygapophysial facets behind; they look backward and downward, and
are separated by a groove from the region of the centrum. Under the
sharp ridge which connects these zygapophyses behind, the neural arch
is excavated, and the cup shows the termination of three canals. The
largest one is the upright oval of the neural canal in the middle,
on each of its sides separated by a narrow bony wall is another
perforation, very variable in size and shape, sometimes b& large as the
neural canal, but usually small and circular. The anterior end of the
neural arch is cut into, so that as seen from above, the straight sharp
anterior margins diverge mesially from each other at a right angle, and
so expose to view a small anterior part of the neural surface of the
centrum. These lines are prolonged forward and outward, to form the
upper margin of the anterior zygapophyses, which are compressed and
prolonged over and beyond the sides of the anterior articulation, from
which they are separated by a slight groove; the anterior and posterior
zygapophyses are connected by a rounded ridge. The anterior end of the
neural arch is excavated, but less so than the posterior end; in the
middle is the oval perforation of the neural canal, and at the sides
other perforations corresponding to those behind are placed a little
in advance of the neural canal. The anterior and posterior articular
surfaces differ in no respect from those of cervical vertebræ.

The inferior surface of the centrum is separated from the sides by two
ridges parallel to the lateral concave outlines of the neural arch;
they extend from sides of the front, more or less well marked, to the
tubercular processes at the base of the sides of the centrum behind.
The dice-box shaped area of the centrum so inscribed is usually concave
from front to back, and concave from side to side behind, and convex
from side to side in the middle; this convexity is only broken in front
by the development of the slight mesial hypapophysial ridge.

The sides are narrow, flattened, look downward and outward, are a
little concave from front to back, round into the centrum and into the
neural arch, and show at about the middle a small pneumatic foramen,
which is variable in size, but largest in No. 8, and sometimes a mere
puncture.

The caudal vertebræ differ in many ways from other animals. They
have neither transverse processes, neural spines, hypapophyses or
hæmapophyses. In the persistence of the neural arch down the tail they
resemble reptiles and birds rather than mammals, in which nothing but
the centrum persists to the end of the tail. The vertebræ are furnished
with vertebral arteries which run through the neural arch parallel to
the neural canal, in exactly the same position as do the vertebral
arteries in the neck-vertebræ of the Llama.




THE BONES OF THE HEAD.

Pl. 11, 12.

The skull of Dimorphodon differs in form and in many important details
of structure from that of Rhamphorhynchus; and both of these types of
skull are strikingly unlike that of the short-tailed animals named
Pterodactyle. Hence, as it will be shown that the Cretaceous fossils
of this class belong to very distinct new genera, there is no reason
for assigning to them by anticipation any class of cranial structures.
The cranium of this type of animal has never been critically described,
and for all that is yet known to the contrary Pterodactyles may differ
between themselves as much as birds or mammals. Their affinities have
been unknown. Therefore, before describing bones it may be desirable
to state the grounds on which the several specimens are referred to
the Ornithosauria. The fossils on which this section of the memoir is
founded are, the basi-occipital and basi-temporal bones, the anterior
portion of a cranium, the back parts of four crania, facial bones, and
the quadrate and quadrato-jugal.

The crania are all no larger than that of the Heron; though from
the Greensand are bones and jaws indicating Pterodactyles both
smaller and larger. The skulls are mostly remarkable for wanting
both basi-occipital and basi-temporal bones. And the specimen of
basi-temporal and basi-occipital corresponds posteriorly with the
Pterodactyle atlas, anteriorly with these crania; it is hence concluded
to have belonged to a similar animal. Being relatively twice as
large, it indicates that in these animals the basi-occipital condyle
was proportionally larger than in known birds; and that animals of
a cognate kind had skulls probably twice the size of these. The
anterior basal part of the hinder sphenoid terminates in a remarkable
triangular surface, with two perforations, which are separated by a
median ridge. Almost entirely corresponding with this is the basal
surface of the anterior part of a cranium, fractured in front of the
pituitary fossa. Therefore, and as it indicates a similar capacity of
brain, it is regarded as belonging to the same kind of animal as the
others ; but being five times the size, it must, if the proportions of
the Heron were preserved, have been part of a head a yard long.

Now, as there is no other animal with the same texture of bone, or
exhibiting with high organization the same diversity of size, these
cranial fragments are referred to the jaws and bones of Pterodactyle.
So marked are their structures that many quarry-men refer vertebrate
fossils to their several orders with almost as much accuracy as would a
practised anatomist.


  Basi-occipital and Basi-temporal.

  Pl. 11.

  Basi-occipital, Owen, _Sup. Cret. Rep._ p. 6, T. 1, figs. 11, 12, 13.

  Case. Comp. Tablet.
   =J=   _c_     7

This bone was not found associated with any set of fossils that
would induce us to refer it to one species more than to another. Its
Ornithosaurian character was probable; and Prof. Owen described it in
his last memoir on the Greensand Pterodactyles.

But though indubitably basi-occipital, it is so anomalous in some
respects that the Professor regarded the under as the upper surface;
since then the investing phosphate of lime has been removed, and the
bone is now described in what appears to be its natural position.

Viewed from above the fossil divides into two parts; the occipital
condyle, and an anterior, wide, transversely oblong extension
terminating at each side in a strong short horn. The posterior half
of the condyle shows large cancelli as though so much of it had been
covered by the articular cartilage. The sides of the condyle converge,
so that posteriorly it is only two-thirds of the width it has at the
foramen magnum, which would appear to indicate a comparatively slight
lateral motion of the head. The condyle is hemispherical posteriorly
and superiorly; there is a depression between it and the great foramen
of the skull; inferiorly it is flat.

It is 7/16 of an inch long; posteriorly 9/16 wide, nearly 6/16 of an
inch high anteriorly. It terminates in front superiorly in an elevated
transverse ridge.

On removing the matrix, the anterior surface of this occipital bone
was found to be concave; yet as nothing but cancellous structure is
seen it may be but imperfectly ossified or more probably, imperfectly
preserved. And the bottom of this cup expands forward in a thin sheet
of bone a quarter of an inch long and half an inch wide, which on the
under side is continuous with the base of the condyle.

On each side of this floor and partly extending in front of it, and
below it, is an irregular piece of bone, half an inch long, resembling
anterior zygapophyses of cervical vertebræ.

Though in most vertebrates the basi-occipital enters into the basal
floor of the skull, the median bones are either so placed that they
rest one upon another from before backwards or abut against one another
nearly perpendicular, so that the basi-sphenoid comes commonly to
underlap and partly hide the basi-occipital. Nowhere among Amphibia or
Reptilia do I know of the reverse position occurring. In some fishes
there is an approach to it. Thus a slight anterior bony expansion of
the basi-occipital in the Cod fits partly into a horizontal slit in
the basi-sphenoid[A]. In the Carp the basi-occipital has a spathulate
basal expansion like that of Pterodactyle, but it is underlapped by the
basi-sphenoid[S]. In some mammals the under side of the basi-occipital
extends further forward than does the neural side, as for example
in the Sheep and Goat; while in a few others, as in the Walrus, the
reverse positions obtain.

[Footnote S: Parasphenoid of Prof. Huxley.]

But it is among Birds that the structure described in Pterodactyle
is evident and characteristic. For although the bony plate under the
sphenoid,--Mr Parker's basi-temporals,--is mostly anchylosed to the
bones about it, and less with the occipital than with others, its
position and relations are quite the same as those of the expanded flap
of this Pterodactyle basi-occipital. Therefore it is identified with
the basi-temporal bones.


  Back of the Cranium.

  Pl. 11.

  Case. Comp. Tablet. Specimen.
   =J=   _c_     8       1

This fossil is an inch high, rather wider, and half an inch long. It
well shows the bones at the back of the skull, the basi-cranial bones,
and the bones posterior to the frontals, which roof in the Cranium.
There are in it striking resemblances to the back of the skull of some
Natatores, as the Grannet and Cormorant, and of some Grallatores as the
Heron, and Gallinaceous birds as the Cock.

_The base of the skull._ The bones here indicated are the
basi-occipital, basi-temporal, and basi-sphenoid. The former two
have come away as from an articular joint, and are wanting. The
basi-occipital does not enter into the floor of the cranial cavity, and
only rims the foramen magnum. But its basi-temporal expansion rests
beneath the posterior part of the basi-sphenoid forming the base of the
skull; its long convex anterior end fits into the concave groove at the
back of the anterior part of the sphenoid. The squamous basi-temporal
bone appears in this species to have been as long as the foramen magnum
is wide, and to have been relatively thicker than in the other form
already described.

The _basi-sphenoid_ is a thin expanded bone forming the floor for the
cerebellum, and terminating anteriorly in a triangular mass, while the
slightly convex part behind, covered with the basi-temporals, is nearly
square. It enters into the foramen magnum, forming its lower part;
and is confluent with the ex-occipitals behind, with the periotic,
alisphenoid and perhaps with the squamosal at the side; and as in birds
all these sutures are obliterated. This is probably the only instance
in the Animal Kingdom in which the basi-sphenoid takes so important
and singular a share in the functions of the basi-occipital bone. The
anterior part of the basi-sphenoid projects below the posterior part,
is nearly flat on the basal surface, and forms an equilateral triangle
with the apex in front and base behind. In the middle of the triangular
bone is a slight longitudinal ridge, and behind the middle of each
outer side a rather large foramen which appears to be the inferior
opening for the carotid artery. The triangular part is hollow and as
long as the quadrate portion. The lateral parts of this anterior bone
are nearly flat. They converge upwards and are rounded in front to
form the boundary of the pituitary fossa, and do not appear to have
terminated in a spine. Above are the alisphenoids.

_The upper part of the skull_ is divided into two segments by a strong
straight transverse ridge, which leaves the occipital bones behind, and
the parietal &c. in front.

The occipital bones anchylosed together are about two-thirds the width
of the foramen magnum, and of the parietal bones, with which latter the
supra-occipital makes an angle of 45°. The surface is irregular, and
especially is marked by a deep concavity just above each ex-occipital.
The supra-occipital projects slightly over the plane of the foramen
magnum, to which the strong ridge bounding the segment in front is
parallel. The great foramen is nearly round, being slightly compressed
at the upper part of the sides: it measures 3/8 of an inch high and is
nearly as wide.

The _occipital bones_ make with those at the base of the skull an
angle of about 145° or 150°. In outline they are a transverse diamond
shape. The mastoid portion is not to be distinguished from the other
bones, but appear to terminate the sides of the strong occipital
crest, which by posterior compression of the squamosals and parietals,
becomes very strong, and makes the backward boundary of the temporal
foss. This crest is in the same plane with the anterior border of the
basi-temporals.

The _parietals_ meet above in a slight ridge. They are two rectangular
bones twice as wide as long, forming a semicircular roof for the brain,
which looks outward and a little backward. Anteriorly these bones
unite with the frontals in a slightly flexuous transverse line; and
inferiorly they are connected with the periotic, the squamosal, and
perhaps with the anterior point of the alisphenoid: they do not descend
to the plane of the articulations of the free quadrate bones. The
surface is smooth, and on the upper part flat, but concave below from
side to side.

Below these parietals are the _squamosals_ and _alisphenoids_, but the
suture between them is not seen. They are in form a trapezium where
the short side is anterior, and the lower third is folded inward so as
to be confluent with the anterior part of the sphenoid. The fold forms
a ridge, which I suppose may run obliquely over the alisphenoid. The
unfolded squamosal part is a flat and smooth oblong, with parallel
sides, the bones are in parallel planes and nearly perpendicular to the
base of the skull. Where the alisphenoid joins the sphenoid, there is
a considerable concavity, above which is a small circular impression.
These strips approximate inferiorly, so that the width of the skull
there is rather more than half what it is at their outer margins. They
shut off the pituitary body in front of them, and appear to form part
of the wall for the orbit of the eye.--The slightly convex, lateral,
squamosal parts above the fold continue the circular transverse outline
of which the parietals are the upper half. They extend anterior to the
parietals, and on the inside give attachment to the frontals. Like the
parietals, they make a sharp bend outward at their hinder border, and
form the lateral terminations of the occipital ridge, which is the
widest part of this fossil.

The only portion of the specimen now to be described is the large
region at each side looking downward, which extends from the occipital
ridge to the sphenoid. It is an irregular pentangular hollow with many
cavities, the hinder of which are for the ear. Two cavities above
these, under the widest part of the skull, appear to be a double
articulation for the quadrate bone. The outer transverse one with
the squamosal is separated by a deep groove from the inner and more
vertical one, which may therefore be regarded as with the petrosal
bone. These excavations form the posterior half of the pentagon. The
anterior half is a smooth rhombus not separable from the basi-sphenoid.

Such is the external appearance of the occipital and parietal segments
of the skull of a Cambridge Pterodactyle. Each segment forms a large
ring of thin bone, inclosing part of a brain-cavity as large as that
of a bird and shaped like that of a bird; and which moreover is made
up of the same bones as the cranium of a bird; and these are in almost
exactly the same proportions as those of the Common Cock.

My own investigations do not substantiate Wagner's discovery, that the
back part of the skull resembles that of the Monitor. Iguana would
have offered a slightly nearer comparison, but they both differ from
Cambridge specimens of Pterodactyles in characters like these.

In the lizard,

  The cranial bones do not enclose the brain.

  There is no division of the back of the skull into an occipital
  segment and a parietal segment by a girdling crest.

  The squamosal bone does not enter into the cranial wall.

  The quadrate bone does not articulate with the wall of the brain-case.

While the peculiar backward development of wings of the parietal in a
diverging V form, give the Lizard skull an aspect of its own.

So that it must be asserted that the differences of these Pterodactyles
from Lizards are so wide as to preclude comparison.

With the Crocodile, in which the cranial bones are massive, and the
quadrate bone firmly packed in the skull, comparison would be no less
difficult.

The Delphinidæ, in both the form of the jaws and of the back of the
head, give some support to Wagler's fancy, in putting the Pterodactyle
into his curious creation, the Gryphi[T]. But in the porpoises the
parietal bones form as narrow a band as they do in the Duck; and are
quite unlike the bones here described. In the Dolphin the two condyles
almost unite into one semicircular condyle (in young specimens), owing
to the enormous development of the ex-occipitals, which almost if
not entirely exclude the basi-occipital from the foramen magnum. The
dolphin moreover has no quadrate bone. But notwithstanding the absence
of a division into occipital and parietal segments, the form and
arrangement of the bones in the skull of the porpoises approximate more
to the Cambridge Pterodactyles than is the case with Lizards.

[Footnote T: The Gryphi are a class of animals intermediate between
Birds and Mammals according to Wagler, and including Pterodactyles,
Ichthyosaurus, Plesiosaurs, Ornithorhynchus, and Myrmecophaga.]

But with Birds the correspondence is so close that it would be
difficult to discover differences. That one of the condition of the
occipital bone seems to be the most important; another is, that from
the relatively smaller size of the cerebellum the parietal bones appear
to cover a larger part of the cerebrum; and a third is the strong
triangular condition of the sphenoid in front of the sella tursica.
With these exceptions there is nothing to distinguish the fossil
described from the cranium of a bird.


  Back of another Cranium.

  Pl. 11. fig. 1, 2.

  Case. Comp. Tablet. Specimen.
   =J=   _c_     8       2

Another cranium has occurred which must be referred to a different
genus. Its preservation is less perfect, but it similarly exhibits the
occipital and parietal segments of the skull. All the bones are blended
together without a trace of a suture.

The _occipital region_ is flat. Its outline is not defined owing to
the extent to which the sharp crest, in which it terminated outwardly,
has been broken away. The occipital condyle is broken off. The foramen
magnum is of an ovate form--flattened at the base. The ex-occipitals at
its sides are impressed as though from contact with the neurapophyses
of the atlas. Mesially, over the foramen magnum is a vertical elevated
crest (now rubbed away), which may have given attachment to a bone
like that post-superoccipital crest described by Quenstedt in the
_Pterodactylus suevicus_. The occipital region makes a great angle with
the flat basi-temporal region, as in birds.

The _parietal region_ is convex from below upward, the lateral parts
converging towards the crown, which however presents a broken and
worn surface. From side to side the squamosal and parietal bones are
concave, owing to the extended occipital crest behind, and the rapid
widening of the skull in front caused by the large size of the brain.

In _front_ is seen a section of the brain-cavity. It is very like in
form to the two halves of a pear put together side by side with the
stalk downward. I have removed some of the phosphate of lime from the
brain-cavity, and although it has not been excavated to the cerebellum,
the great depth of the brain is well seen, and the convex character of
the cerebral lobes, between which a crest of bone descends mesially as
in the ethmo-sphenoid mass next described. At each of the lower outer
angles of the brain, extending into the cancellous brain-walls to the
outermost film, is an ovoid convexity, covered with a thin film of
bone. They entirely correspond with the optic lobes, being in exactly
the same position as in birds, only relatively rather small. Underneath
the optic lobe on the outside is a small concavity, apparently the
articulation for the quadrate bone. The basi-sphenoid mass below the
brain is of considerable height, the upper half flat and smooth, the
lower half fractured and cancellous.

In the main this skull is like the other one, differing chiefly in the
depth of the sphenoid, in the mesial ridge between the cerebral lobes,
in showing the optic lobes, and in having anchylosed basi-temporal
bones. There would hence appear to have been considerable variations in
the skulls of Pterodactyles even in the Cambridge Greensand.


  Orbito-ethmo-sphenoid bone.

  Pl. 11.

  Case. Comp. Tablet.
   =J=   _c_     9

The symmetrical bone which I have so named is a wedge-like mass
tapering in front, keeled above; flattened below, and cupped behind
on each side. It belonged to a very much larger animal than the last
fossil, and probably to a very different genus.

The _inferior surface_ is triangular, an inch and an eighth wide
behind, at the base, and an inch and a quarter long; but it is broken
at both ends. In its longitudinal median line is a strong keel stopping
short in front, dying away behind, and forming with the compressed
margins a considerable hollow on each side, at the back part of which
is a large oval foramen. This surface, though five times the size,
corresponds in form, ridges, and foramina with the anterior part of the
sphenoid described in the article on the back of the cranium.

The _posterior surface_ is at right angles to the inferior one, but its
lower third shows only fractured phosphate of lime filling perhaps the
anterior part of the pituitary fossa. Its upper part also is broken.
But on each side is a large concavity measuring in the fractured fossil
an inch and a quarter high, three quarters of an inch wide, and half
an inch deep from the unbroken median ridge where the cups become
confluent at their base. The whole specimen is two and a quarter inches
high. From the determination of the under side it follows that these
smooth hollows, over each of which an impressed mesial line descends
obliquely outward, are a part of the anterior boundary of the brain.

From the middle of the outer convex border of the oval remains of
these cups for the cerebral hemispheres, a strong blunt ridge descends
obliquely down the sides of the bone to terminate the compressed
anterior end of the bone just in front of the hypapophysial ridge of
the sphenoid. Above this ridge the bone is much compressed anteriorly,
forming a strong straight mesial keel above, which rapidly approximates
to the base; the height of the bone in front being one inch and a half,
which is also its extreme length.

The region below the oblique ridge is a concavity, but it is a little
compressed from side to side behind, and has the same anterior
compression, so that the elongated oval of the fracture at the anterior
end of the bone is only three-eighths of an inch wide.

The superior ridge will probably have supported the frontals, and the
anterior end would terminate in the orbito-sphenoid.

The lateral ridges appear to correspond with what Prof. Huxley has
described in the Ostrich as the ridge indicative of a supra-presphenoid
ossification pointed out by Kölliker. The groove which is here noticed
on the cerebral surface may indicate the same division. If so, the
upper and anterior part of the mass would be the ethmoid.

This mass offers a considerable resemblance to the frontal portion
of the skull of a dolphin (_e. g._ Delphinus delphis) from which the
maxillary, premaxillary, palatine and nasal bones have been removed.
But in the Porpoise the mesial ridge dividing the cerebral hemispheres
is not prolonged so far forward as in the Pterodactyle; the cranial
bones are often as smooth on the inside. Notwithstanding Wagner's
assurance that the Pterodactyle skull is very like a Monitor's, he
would have looked in vain for an ossification in Monitor, Iguana, or
other Lizards, comparable with this mass. And although the brain is
closed in front by bones in Serpents, it is by the frontal bones,
which form a covering for nearly the whole of the conical cerebrum.
Nor in the Crocodile is there any ossified mass in front of the brain,
although the brain approximates nearer to Birds than is the case with
other living Reptiles. Among Birds such a structure as that of the
Pterodactyle is characteristic, but no bird has it so massive and
mammal-like, though an approximation is made in some thick-skulled
birds like _Ciconia marabou_. And in birds it usually is prolonged much
further forward than appears to have been the case with Pterodactyle,
where from the rapid tapering of the mass in front it appears to have
ended in a vertical ridge like that in Parrots and Birds with a
moveable beak. In Birds there is usually a median ridge dividing the
cerebral hemispheres, but there is also often a small olfactory lobe
prolonged in front of the cerebrum, to which nothing analogous is
indicated in these fossils.




NATURAL MOULD OF THE BRAIN CAVITY OF A CAMBRIDGE ORNITHOSAURIAN[U].
(Cast.)

Pl. 11.

[Footnote U: For the opportunity of making this description, I am
indebted to the kindness of John Francis Walker, Esq., M.A., F.G.S.,
F.C.S., &c., who some time since forwarded to me the whole of his rarer
Ornithosaurian remains for description in the Geological Magazine,]

The original specimen is in the collection of J. F. Walker, Esq., of
Sidney Sussex College. When found it only displayed the front of the
cerebral hemispheres, and Mr. Walker generously gave me permission to
remove the investing cancellous bone and phosphate of lime, and thus
exhibit the form of the cerebrum and its relations to the cerebellum.
The lower part of the brain is not preserved. But adherent to the sides
of the fossil are still left parts of the temporal bones, and part of
the bone at the back of the orbit which closes in the brain. The form
of the cerebellum is not quite perfect behind, but it must have been
unusually small.

The cerebral lobes taken together are much wider from side to side than
from back to front, and have a transverse elliptical outline, except
for the mesial notch behind for the cerebellum. The lobes are a little
flattened above, and divided from each other by a deep mesial groove,
which makes each lobe convex from side to side. They are well rounded
at the front and at the sides, and are a little compressed towards each
other below in the region of the orbits. Behind they become covered
superiorly as in birds with a greatly thickened part of the squamosal
and parietal bones. The surface of the cerebrum is smooth. There is
no indication of a pineal gland. The cerebellum is small, like a pea
between two filberts. It is sub-hemisphercal, is placed close against
the cerebrum, and appears to give off narrow lateral parts, like
those seen in many birds, only that they abut against the back of the
cerebral lobes as in the Hare and some Mammals. In no reptile is there
a brain in which the cerebrum embraces the front of the cerebellum,
or in which it attains to such an enormous size. Fœtal Mammals (_e.
g._ the horse and the sheep), even when they have attained to a
considerable bulk, and many adult mammals, still have the optic lobes
dividing the cerebrum from the cerebellum as in Reptiles.

The only Mammal which shows any near approximation to this brain is
the _Ornithorhynchus_, in which the cerebellum is very small, but the
cerebrum is not so well rounded in front. The form approximates to
the brain in Man. But with Birds the resemblance is so close--with
the owl and the goose--that there is no character to distinguish the
brain of the fossil animal from those of the recent ones. A section of
the cerebrum in this specimen entirely corresponds with a section of
the brain-cavity in the second skull described, as does the backward
extension of the cerebrum with the extent of the cerebral cavity, and
the narrow cerebellum with the narrow channel parallel to the walls
of the foramen magnum, as in _Gallus domesticus_ and Birds. The front
of the brain corresponds with the cast of the front of the cerebral
lobes taken from the Ethmo-sphenoid mass. Thus the specimens agree
among themselves, and prove the Pterodactyle to have had a brain
indistinguishable from that of a Bird. And when it is remembered how
distinctive this kind of brain is, and that it approximates rather
towards the higher Mammals than towards Reptiles, the fact attains
unusual importance in determining the Pterodactyle's place in nature.



?NEURAL ARCH OF SACRAL VERTEBRA, ?VOMER.

Pl. 12.


Frontal(?) Owen. _Palæontographical_, 1859

Pl. 4, fig. 6, 7, 8.

  Case. Comp. Tablet. Specimen.
   =J=   _c_    10      1-3

In 1859 Prof. Owen described with doubt as the Frontal
of Pterodactyle, a symmetrical bone. A smaller but more perfect
specimen has since been obtained for the Woodwardian
Museum; and a fragment of intermediate size is in the rich
collection of the Rev. T. G. Bonney. From the descriptions
already given it is impossible for it to be the frontal. There
is no proof that it is a skull bone. If of Pterodactyle the
compressed lateral spaces could only be part of the nasal passages,
or the impressions of a palatine or pterygoid articulation.
And as the external surface of every specimen is keeled, and
as the palatal surface of the upper jaw of every known Greensand
Pterodactyle is keeled, and as the concavities slightly converge
to the keel, it might be a bone from the under side of the
head,--the vomer.

The smallest specimen is a compressed sub-semicircular bone
1-1/4 inch long, 9/16 inch high, and a 1/4 inch thick. The under surfaces
converge to form a strong keel, which is flattened off behind.
Above this, the posterior third of the bone is compressed
obliquely to half the thickness, as though a bone had over-lapped
this area on each side. If the oval spaces are nares, that
bone might have been the pterygoid or palatine. Three-fifths
of the remainder of the bone are taken up by the smooth oval
depressions, which might be the inner walls of the nares; and above
this is a margin of bone widening into the triangular compressed
part in front, which, if the fossil is rightly determined, must have
fitted into the posterior end of the maxillary or anterior end of
the palatine bones.

A specimen collected by the Rev. T. G. Bonney is preserved on
the sacral side of a left _os innominatum_ with the keel downward.
It appears to show a sutural surface from which an anterior part
has come away. And if this specimen is compared with the
neural arch of the sacral vertebra =J=._c_.4.1, it will be found to
correspond entirely. It is not impossible that _c_.10.1, 2 may be
vomerine, and _c_.10.3 sacral, but there are no distinctive characters
between the specimens to warrant such a determination.


  QUADRATUM.

  Pl. II.

  and Quadrato-Jugal.

  Case. Comp. Tablet. Specimen.
   =J=   _c_    11      1-4

In the Woodwardian Museum are two distal ends of the quadrate bone and
two other fragments showing the quadrato-jugal with it.

_Quadrate._ The smallest specimen is 1/2 an inch over the articular
surface for the lower jaw and a quarter of an inch thick. It is concave
from side to side in front where it shows a large pneumatic foramen
near the basal end; it is bent from the articulation a little backward.
It is convex behind; and between the foramen and the articulation sends
inward and forward a great wing like that of the quadratum in birds.
The specimens are broken short off and do not show any articulation
above, where the bone contracts.

The distal articulation is double, like two long cones placed together;
that in front having the base outward, while the hinder one has the
base on the inner side. The largest specimen, which is much broken,
shows the articulation half an inch thick.

_Quadrato-jugal._ This is a thin flat squamous bone, apparently of a
transverse diamond shape, which is anchylosed to the anterior lateral
margin of the quadrate, at right angles to the articulation. The lower
margin is straight, as is the upper anterior margin, which appears to
have received the malar bone above.

The upper posterior side is broken, but shows a large foramen near
to the side of the quadrate. The base of the diamond is at the
articulation, and at its apex is a small fragment of smooth surface,
either part of a foramen, or the orbit of the eye.

In this specimen the articulation, which is broken, is about 3/4 of an
inch wide, 3/8 of an inch thick. The remaining piece of the quadrate is
an inch long. The quadrato-jugal is an inch and 3/16 high, and between
its broken ends 1-3/4 inch long. It is thick and strong where joining
the quadrate, but the rest of the bone is about an 1/8th of an inch
thick.

The quadrate bone is Avian in possessing a pneumatic foramen, and Avian
in the form of so much of the distal end as is preserved, and in the
articulation for the lower jaw. The process which it sends inward on
the inside is probably for the pterygoid bone, after the manner of
Birds. Before anchylosis with the quadrato-jugal bone set in, as may
be seen in =J=._c_.11.4, the union was made by a hemispherical knob on
the outside of the quadrate, as in _Gallus domesticus_. The squamose
quadrato-jugal is a distinctive character.


  ?PTERYGOID END OF PALATINE BONE.

  Pl. 12.

  Case. Comp. Tablet. Specimen.
   =J=   _c_    14      1-2

This determination is conjectural. Its form is such as would make it
probable that it is part of the head. A more perfect specimen is seen
in =J=._c_.1.2.7.

The best specimen is a compressed sub-quadrate fragment of bone
terminating at one end in a long reniform articular surface, and at
the other end in a fracture where the bone is rapidly thickening. A
side, regarded as the outer one, is flattened, being slightly concave
in length, and slightly convex from side to side. The form of the
inner side of the bone is determined by the inward curve of the thick
part of the articular surface, which sends a rounded ridge obliquely
on to the side, so that while it is concave from side to side at the
articulation, at the fracture it is convex from side to side. All the
specimens are large, the articulation being not less than an inch long.


  PREMAXILLARY BONES

  Pl. 12.

appear to be developed as in birds. An account of their structure will
be found in the notes on the species, page 112.

                   ------------

  OS ARTICULARE AND PROXIMAL END OF LOWER JAW.

  Pl. 12.

  Case. Comp. Tablet. Specimen.
   =J=   _c_    12      1-6

Prof. Owen has described in a 'Palæontographical' monograph the
proximal end of a mandible in which the sutures are obliterated.
But there is one specimen of a young right ramus showing the inner
and under part of the mandible to be the surangular bone which
unites with the angular or outer bone by a longitudinal and vertical
suture traversing on the inner side the great upper groove; and on
the surangular the greater part of the articular bone rests. The
articulation is strong and double, consisting of a deep transverse
hollow, bounded by a strong over-locking ridge in front and a slight
ridge behind; and this area is divided into two tapering furrows by
a strong oblique and rounded crest, which passes from behind inward
and forward. Just behind the articulation is a ?pneumatic aperture,
and then the upper surface tapers to the under surface, forming a
heel, of which one specimen measuring an inch deep on the inside of
the articulation has 3/4 of an inch still left and is more than 1/4
inch thick at the fracture. In a specimen belonging to the Rev. T. G.
Bonney the outside of the jaw is 11/16 of an inch deep, and under the
articulation 5/16 of an inch deep. The articular area is 3/4 of an inch
wide and 6/16 of an inch long.

Seven specimens indicate four species.

The proximal end of the lower jaw is entirely Avian. The pneumatic
aperture, as in birds, is placed behind the articulation, which is
shaped as in many birds. Commonly in Ornithosaurians the bones are
anchylosed and all trace of sutures obliterated, as in most birds. In
the Goose, however, the six elements of each side are sometimes as
readily separated as in reptiles. And in some Pterodactyles the bones
separate.


THE DENTARY BONE

Pl. 12.

The dentary bone consists of a single piece, as in birds and
chelonians; and differs from both in being provided with teeth. It is
described under the species O. machærorhynchus, page 113.

                   ------------

  THE TEETH.

  Pl. 12.

  Case. Comp. Tablet. Specimen.
   =J=   _c_    17      1-39

The first three teeth are usually larger than those which are
placed behind them, in this respect rather resembling some fossil
reptiles than Dolphins, and presenting a character like that seen
in the Dimorphodon. They are placed in oblique oval sockets. They
have a single fang like Cetaceans, Edentates, Reptiles, and like
the premaxillary teeth of Mammals. Cambridge specimens of jaws are
not sufficiently perfect to show whether the teeth are limited
to the premaxillary bone; but this appears to be the case in
_Pterodactylus crassirostris_ (Goldf.), and probably in _Ornithocheirus
compressirostris_ (Owen), [_Palæontographical Society_, 1851, Pl. 27],
and is so regarded by Professor Owen in his later writings. Yet the
significance of this fact seems to have been forgotten, and Cuvier's
dictum about their teeth still has influence. He says, "The teeth, by
which the examination of an animal ought always to be commenced, here
present nothing equivocal. They are all simple, conical, and nearly
alike, as in the crocodiles, monitors, and other lizards." But, on the
one hand, the Dolphins demonstrate that a mammal might have similar
teeth even in the maxillary bone; and, on the other hand, since teeth
in the premaxillary bone always are single-fanged, and commonly have
a simple sub-conical crown, there is absolutely no evidence in the
teeth of the affinities of the animal, which, so far as this portion
of its economy went, might as well have been a fish or a mammal as
anything else. In the succession there is nothing very distinctive.
In the Crocodile one tooth comes up under another, as is commonly
the case with mammals; and in mammals the fangs of the old teeth are
often partially absorbed so that the teeth drop out into the mouth. In
the Pterodactyle the new teeth came up on the inner side, as in the
Ichthyosauria--a tribe of animals as singular in their affinities as
the Ornithosauria. Occasionally specimens show a small furrow on the
inner side of the fang, indicating absorption, but there is nothing
to show how many times the teeth were renewed: in the Dolphins there
is but one set, and in Crocodiles the teeth are replaced many times.
In form and size the teeth are very variable. They are directed
obliquely forward, and are curved backward and inward. They taper
in an elongate cone, compressed from side to side, flattened on the
outside, moderately convex on the inside; rarely the sides meet in a
ridge after the plan of Pliosaurus, Megalosaurus, Dakosaurus, &c.;
more frequently the lateral margins round into each other. Usually
the enamel is quite smooth, sometimes, as in No. 1, it is finely
striated and wrinkled. Some teeth are nearly circular and some quite
straight. The ovate fang contracts below, conically, and is closed,
leaving a long hollow pulp-cavity in its interior. Nos. 9, 10 show the
marks of the successional teeth on their inner sides. No. 11 appears
to have had the crown slightly worn at the tip during the animal's
lifetime. In transverse section of the crown the tooth structure
resembles Ichthyosaurus, Cetaceans, and Bats. The dentine is filled
with calciferous tubes which radiate as in Ichthyosaurus, and towards
the centre of the tooth are seen in transverse section to present
many angles, almost like radiated corpuscles. They are separated by
interspaces of their own width, and run towards the circumference,
sometimes straight and sometimes wavy, parallel to each other. They
send off branches usually at right angles which anastomose with the
adjoining tubes. The dentine is in concentric layers, and shows layers
of sub-circular cells as in the teeth of Mammals. The enamel is a thin
transparent layer with fewer and finer tubes than the dentine.

                   ------------




A SUMMING UP.


The story of the structure of the Ornithosaurians of the Cambridge
Greensand has now been told, and it only remains to gather up the
threads of their affinities and determine the Pterodactyle's place
in nature. But before doing so, so various in importance are the
characters enumerated, that I would first offer a few remarks on the
classificational value of characters among the Reptilia, with which
Pterodactyles have been most commonly grouped.

The naturalist who only examines organisms now living on the earth,
symbolizes to himself, by the term Reptile, a definite sum of
characters, with definite subdivisions and subordinate grouping, to
which the extinct types of life extricated from the rocks cannot
entirely be adapted. When the fragmentary, and often isolated or
ill-associated, bones of fossilized animals are contrasted with
corresponding bones in the skeletons of Serpents, Crocodiles, Lizards
and Turtles, not infrequently it is found that the characters
attributed to different Ordinal groups are interlaced in a single
individual with a type of organization peculiar to itself, and
important as are the modifications of existing orders. These characters
occasionally are grouped with others which in living animals had been
deemed characteristic of Fishes, Amphibia, Birds, and Mammals.

The Reptilia of the Palæontologist is therefore a vast and provisional
group, ever acquiring new characters, to which no diagnosis can be
applied. And although certain empirical characters have served to
allocate the specimens in their several orders, in general with
sufficient accuracy, yet from the imperfect preservation of some of the
remains, or the imperfect extent to which their structures are known,
and the want of recognised canons by which to measure their relative
values, it has not been possible to discuss the relations of the
several orders to each other or with the larger groups on which some of
them impinge.

Classifications represent more or less faithfully the gradational
increase in the sum of the characters of an organism, as well as the
increase in importance that those character severally attain. Thus
gathering, so far as may be, from the chaos of individuals, _a common
plan of structures_ on which the genus, order, or class is moulded
from a less specialized group of organs. The fundamental structures
of a vertebrate animal, so far as their persistent importance can be
measured, are, those connected with

    I. Perpetuating the race.

   II. Construction of the brain.

  III. Circulation and oxidation of the blood.

   IV. Locomotion, i.e. skeleton, muscles, &c.

And these characteristics are for the most part so interlinked, that
it becomes difficult to assign to one order of animals a relative
superiority over another order; since when a single set of organs is
prominently developed in one group it often happens that another set of
organs has a like pre-eminence in an allied group. Thus among reptiles
it might be considered that

  _Crocodiles_ have the best hearts, and _Turtles_ the best lungs.

And since these structures in their functions severally modify and
determine the use of other structures, the meaning that terms like
Crocodilian and Chelonian really have is that they represent the
aspect of Reptilian organization when seen through the specialization
of respiration, or circulation of the blood. The soft parts thus
determining the nutrition and function of the muscles and skeleton,
anatomists in examining the bones of extinct animals are accustomed to
reverse the order of their inferences, and infer from modifications of
the skeleton what had been the characters of the soft and more vital
structures.

On the presumed accuracy of this method of research rest many results
of Comparative Anatomy. But since the shapes of bones are determined by
the muscles as well as by inheritance, it is always to be remembered
that a similar form of bone may obtain in different orders or classes
of animals, as the result of a similar function in a special region of
the body. Such resemblances are familiar to anatomists. Hence much
caution is required from the Palæontologist to distinguish between
the characteristics of a group, and the extent to which they may be
modified by function. This distinction is the first principle of
classification. But it is always difficult to estimate the importance
of characters in fragments of bones or parts of skeletons, and the
difficulty is increased by the fact that if what appears to be but a
functional modification should pervade all the species, it becomes
a characteristic of the group, and its power of modifying the other
organs in a peculiar way has to be considered.

Thus for all practical purposes birds may be said to be characterized
by wings, which almost acquire the dignity of class characters from
their influence on the respiratory function. But in some birds it has
been thought that no bone of the fore-limb was ever developed[V]; and
the difference between such a phenomenon and the wing of a Swift, for
example, is one almost of infinity, as compared with any other aspect
that the anterior limb might have assumed. Therefore, since a bird may
part with its fore-limbs and yet remain a bird, I infer that it might
apply its fore-limbs to the ground, become a quadruped, and be a bird
still. And if in this process the other structures remained unchanged,
no one would regard the modification as more than an ordinal one. But
should the vertebræ change also, or the pelvis, or the covering of
the integument, or the jaws become toothed, then, although the heart
and lungs and brain of the imaginary animal retained their class
characters, the functional differences being more than those of an
order would constitute it a sub-class.

[Footnote V: According to Prof. Owen, in Dinornis.]

In the same way it is conceivable that serpents may have existed with
well-developed limbs, and if they retained their other characters the
limbed forms would constitute a sub-order of serpents; but if to these
characters they added a closed palate united to the cranium, they would
constitute a new order of reptiles. A chelonian might be entirely
deprived of its bony covering, and it would still be a chelonian,
differing only as a separate family. So that structures which to the
eye appear fundamental may be lost without affecting an animal's
systematic position, just as animals while resembling each other in
form may possess dissimilar organization.

Even with the living or typical Reptilia, naturalists are divided as
to the number of ordinal groups into which they naturally fall. It is
however generally agreed that the Amphibia or Dipnoa of Fitzinger, have
no near affinity with the true reptiles. Milne-Edwards, Van der Hoeven
and Agassiz make the remainder into three orders, as did Cuvier:

  Chelonia,
  Sauria,
  Ophidia.

Stannius, Gray, Owen and Huxley, on the other hand, by dividing the
Saurians make four orders, to which Dr Günther by his description of
Sphenodon has given evidence of a fifth:

  Crocodilia,
  Chelonia,
  Sauria,
  Ophidia,
  (Rhynchocephalia.)

De Blainville in a remarkable classification (1816), made three orders,
Chelonians, Emydosaurians [crocodiles], and Saurophidians; the latter
group being subdivided into Saurians and Ophidians.

In his "Handbuch der Anatomie der Wirbelthiere" Stannius unites the
Crocodilia and Chelonia into a group called Monimostylica; while of
the Sauria and Ophidia he makes another group called Streptostylica.
Similar groups were made by Dr Gray, and named Cataphracta and
Squamata. They are identical with the "cuirassed" and "scaly" reptiles
of Dumeril and Bibron.

The _Astylica_ (Sphenodon) have no penis.

The _Streptostylica_ have a double penis, lungs simplified at the
distal end into a mere air-bladder, brains with a moderately elongated
cerebrum, the palate mesially open, scales, leathery shell to the egg
cut through by a tooth on the premaxillary bone.

The _Monimostylica_ have a single penis, lungs well subdivided,
ventricle of heart partly [turtles] or entirely divided [crocodiles],
brains having the cerebrum broad or high, a closed palate, scutes, a
calcareous shell to the egg.

Thus the chief differences between Turtles and Crocodiles on the one
hand, and Lizards and Serpents on the other hand, are not so much
in the fundamental vital structures, though these undergo changes
even in the families, as in the different ways in which the muscles
and skeleton are modified. The typical lizards diverge widely from
the crocodiles, and in those osteological features which admit of
comparison they make at least as near an approach to the Chelonians.
But leaving the limbs and pectoral and pelvic girdles out of
consideration, lizards find their natural place side by side with the
serpents.

Attempts have been made by Palæontologists to incorporate the new
ordinal groups which they have been compelled to create for some
fossils, along with the true Reptilia; but such a proceeding destroys
the value of the term Reptile as a measure of a known organization. In
the absence of knowledge of the brains of Dinosaurs, Ichthyosaurs, and
Dicynodonts, their union with the Reptilia can only have a stagnating
effect on Palæontology, for there is no proof that they are Reptiles
in the same sense as are Crocodiles or Chameleons: while their bones
being used as standards of Reptilian structure in comparisons, they
adjudicate the place in nature of other animals by an authority which
has never been established.

Before any inference can be drawn from the forms of bones in extinct
animals, their relations to vital structures and to way of life must
be known in animals which still live. This may give some clue both
to their functional significance and to the extent to which they are
inherited and not directly attributable to function. But an idea of
the morphological value of the bones of living animals is only gained
by comparing them with the remains of their extinct allies, tracing
the now imitative structure back to its origin in a function which has
ceased to be displayed.

Professor Owen in his "Comparative Anatomy of the Vertebrates" (1866)
admits nine orders of Reptiles, five of which are extinct, some of the
extinct orders being supposed to rank lower, while others are higher
than the living types. They are arranged in this way,

      * Pterosauria,
      * Dinosauria,
        Crocodilia,
        Ophidia,
        Lacertilia,
        Chelonia
      * Anomodontia,
      * Sauropterygia,
      * Ichthyopterygia.+

  * Extinct.

  + Prof. Owen, _Comp. Anat._ Vol. I. p. 7-9, defines his
      sub-classes. At p. 15, in the details of the orders, he puts
      Ichthyosaurus in the 5th sub-class _Monopnoa_. But at p. 50,
      treating of the vertebral column of Ichthyosaurus, it is written of
      as an extinct order of _Dipnoal_ reptiles. The Dipnoa then
      would include

        Ichthyosauria,
        Batrachia,
        Labyrinthodontia,
        Ganocephala.

      But Ichthyosaurus obviously belongs to Haeckel's group Monocondylia.

In what characters the Ichthyosaurs are lower than living reptiles I
have been unable to discover. The palate may be better compared with
a struthious bird than with a reptile; and the pectoral girdle may be
better compared with the Ornithodelphia than with a reptile, while all
the trunk-vertebræ have ribs such as are associated in living animals
with a four-celled heart. But if it is a lower animal type than living
reptilia, the student will ask, how much lower? does it descend to
the Dipnoa, and prove to be the missing link between the Amphibia and
Reptilia? and wherein is the evidence? Or does it not with Dicynodonts
and Dinosaurs rather form an outlying class uniting the reptiles with
the mammals.

In the same way, when Pterosauria and Dinosauria are placed above
living reptiles, we are compelled to ask how much are they above, or
what are the characters which bind them to the Reptilia at all? No
satisfactory evidence has ever been adduced to show that the Dinosauria
are Reptiles. And of the claim of the Pterodactyles to such a position,
the facts detailed and now summarised will be the best evidence.

The highest structure shown in these remains is the brain-case. The
cavity for the brain is in every respect like that in the skull of a
bird. It resembles brains of a high type in having the cerebral lobes
convex in front; since, in the lower mammals, there is a resemblance
to reptiles in the conical form of the cerebrum; while the brains even
of some of the placental mammals are not well distinguished from those
of reptiles. Although the brain of the Ornithorhynchus is entirely
mammalian, it is more like the brain of a reptile than is the brain
of the Pterodactyle. No evidence of affinities could be adduced which
would outweigh this. Taken by itself it would lead us to anticipate for
the Pterodactyle those vital structures which birds have in common.

Next in importance to the brain are the pneumatic perforations in
the bones. They are seen in the lower jaw, the quadrate bone, in the
whole of the vertebral column, in all the bones of the fore-limb,
excepting one or two fragments, in the scapula and coracoid, in the
os innominatum, in the femur and in the tibia. In such of the bones
as can be compared, the pneumatic perforation is usually situated in
Birds as it is in Pterodactyles. In Birds the bones are filled with
air through these perforations, and as a principle the greater the
motion of the animal, the greater is the number of bones filled with
air. This air is received from the air-sacs which receive it from the
lungs, and return it through the lungs again. There is thus in birds
a sort of supplemental lung-system, which circulates air through the
body. Nothing of the kind exists in any other class of animals. The
respiratory system in birds is more perfect and complex than in the
other vertebrata, and, as a result, the temperature of the blood on the
whole is hotter.

In Pterodactyles the reticulate character of the perforations proves
that they were pneumatic, and supplied the bones with air. The fact
that the bones were supplied with air, necessitates an elaborate system
of air-sacs to furnish the supply. And the existence of these air-sacs
speaks incontestably to bronchial tubes opening on the surface of the
lungs to supply them, and to the existence of lungs essentially like
those of birds. The outward and backward direction of the coracoid
bones may indicate that the lungs were larger than in a bird.

The circulation of air through the bird's body has relation to rapid
motion through the atmosphere, which necessarily produces more rapid
respiration than would comparative quiescence. The same inference must
be applied to the Pterodactyles. But rapid respiration only means more
rapid oxidation of the blood, and conversion of the purple cruorine
into scarlet cruorine,--that is, the conversion of venous blood into
arterial blood. And if venous blood is converted into arterial blood by
a lung-apparatus like that of a bird, and with a rapidity like that in
a bird, there must be a circulation of the blood as rapid as in birds.
Such a circulation is only maintained by a heart with two auricles and
two ventricles. Therefore Pterodactyles had the heart like that of
birds and mammals.

Now, since the temperature of the blood is chiefly dependent on
respiration and circulation, and Pterodactyles had respiratory and
circulatory organs which in living animals produce hot blood, it
results that they were hot-blooded animals.

Thus the heart and lungs are exactly such as would have been inferred
from the brain, and, like it, they are avian. And so important are
these vital structures all taken together, that the inference from them
upon an animal's affinities would overbear all other evidence that
could be adduced except reproduction; for they demonstrate the plan on
which an animal was built, and are the motor power which enabled it to
use its skeleton in a way that stamped upon it a peculiar form.

In the head such structures as are preserved conform with slight
variations to the avian plan. Other Ornithosaurians show in the parts
which are not preserved in Cambridge specimens some characters which
are not avian; they are in part as much mammalian as reptilian, and
in a few points entirely reptilian. But it might be misleading to
take German specimens into consideration in forming an estimate of
the Pterodactyles of the Cambridge Greensand, which were probably a
different ordinal group, and may have had material differences in
structure.

The vertebral column as a whole is distinctive.

The neck and sacrum are mammalian, and the tail reptilian. The
procœlous vertebræ are characteristic of reptiles, but in some animals,
as Chelonians, they vary in different regions of the body; and among
amphibians the character is inconstant in genera nearly allied.

The hind-limb is in part mammalian and in part avian; if there be any
reptilian characters in the foot, they are not less mammalian.

The os innominatum is avian and mammalian.

The pectoral girdle is avian.

The fore-limb is avian and mammalian.

The wing-finger is distinctive, though formed on the avian plan.

Thus, if with an avian basis some parts of the skeleton present points
of agreement with reptiles, in other points there are resemblances
with mammals not less characteristic. These phænomena do not show that
in so far the animal is a mammal or a reptile, but only that mammals,
ornithosaurians, and reptiles have had a common origin, and that while
they have been differentiated so as to form separate classes they have
severally retained characters which formerly were united in one class.
It is a skeleton intermediate between reptiles and mammals, and well
distinguished by mammalian, reptilian, and peculiar characters, from
birds. It therefore forms a parallel group with birds, displaying
the ornithic organization in a differently modified skeleton. Yet it
differs more from existing birds than they differ among themselves,
for the discrepancies are in points of structure in which all existing
birds agree: they are in having teeth, in the procœlous centrum, in the
separate condition of the carpal and metacarpal (and of the tarsal and
metatarsal) bones; in having more than two bones in the fore-arm, in
the sacrum formed of few vertebræ, in the expanded pubic (and prepubic)
bones, in a long neck to the femur, and in the modification of the wing
by the great development of the phalanges of one finger.

I therefore regard the Pterodactyles as forming a group of equal value
with birds, for which group the name Ornithosauria is here used.
It cannot form a separate class, because they have a fundamental
organization in common; and it cannot form an order of birds, because
its differences from birds are greater than those of an order. It
is a group which itself probably includes several orders, and must
constitute a sub-class, which finds its place in nature side by side
with birds and between mammals and reptiles, thus:--

  Mammalia. \
            |
            | Ornithosauria.     Aves
            |
  Reptilia. /


Restoration.

Of the form and size[W] of the animals from the Cambridge Greensand, an
idea will best be given by a few measurements.

[Footnote W: There are Ornithosaurians hereafter to be described
compared with which the largest at present known will seem diminutive.
A vertebra of one such, from the Wealden, is contained in the British
Museum (numbered 28632). The centrum alone is between 9 and 10 inches
long and 8 inches deep. It is named Streptospondylus, but constitutes
a new group of Ornithosaurians. Nothing so gigantic exists in the
Woodwardian Museum. Another vertebra of the same or an allied genus has
been figured by Prof. Owen as the tympanic bone of ?Iguonodon (Fossil
Reptilia of the Wealden, Part 2, pl. 10).]

In the species Ornithocheirus nasutus (Seeley), =J=._c_.2.11.1:

The premaxillary extends for 6 inches without reaching the nares.

The lower jaw is 3/4 of an inch deep at the articulation.

The four cervical vertebræ are each 1-1/2 inch long.

The sternum measures 1-1/2 inch over the facets for the coracoids.

The humerus is 2-1/16 inches over the proximal end, the radial crest
not being preserved.

The coracoid is 1-1/4 inch over the proximal end.

The scapula is about 3-1/2 inches long.

The proximal carpal (imperfect) is 1-5/8 inch wide.

The distal carpal is 1-1/2 inch wide.

The lateral carpal is 1-1/4 inch long.

The wing-metacarpal is 1-1/4 inch wide at the proximal end, and 7/8
inch wide at the distal end.

The proximal end of the first phalange is about 1-5/8 inch wide.

The proximal end of the second phalange is less than an inch wide.

The claw-phalange (imperfect) is about 1-1/4 inch long.

The femur is 4 inches long.

Putting the animal together, the bones give this size :

  Head                     1 ft. 3 in. long.
  Neck                           9    "
  (_Back and sacrum_)    ?  8    "
  (_Tail_)               ? 10    "

With the hypothetical parts, this would give a length of about 3 ft. 6
in. from the tip of the snout to the tip of the tail. Then

    Humerus                8 in. long.
    (_Fore-arm_)   ?1 ft.  0    "
    Carpus                 2    "
    Metacarpus            10    "

Which, if the fore-limbs were kept together as in ordinary quadrupeds,
would give a height to the body of about 2 ft. 6 in., but as the limbs
probably spread in walking as among the bats, the hind-limb would give
a better idea of the height of the animal.

    (Flesh, sacrum, os innominatum). 2 in.
    Femur                            4  "
    (_Tibia_)                       6  "
    (Metatarsus, &c.)                1  "

Which would give a height of about 13 inches; and, standing in the
position of a bird, the height to the crown of the head would be about
2 feet. The majority of the Ornithosaurians of the Cambridge Greensand
are of this size.

The spread of the wings, if there were 4 phalanges, would be

    Body                      10 in. wide.
    Two arms            5 ft.  2    "
    Two wing fingers    7      0    "

Giving a total expanse of about 13 feet. But, from the indications
of the wing-finger, I should incline to think an expanse of 10 feet
a truer estimate. The largest species attained to twice this size,
and the smallest was a fourth as large. Another memoir will present
descriptions and restorations of the Greensand species.


Habits.

The varying organization of different Ornithosaurians probably depends
on the different habits of the tribes. That they could all fly is
probable from the enormous radial crest to the humerus and the great
development of the wing-bones, to which a wing-membrane was stretched,
comparable to that of a Bat in texture, but more comparable to a
Bird in its extent. The groups with long hind-legs probably had the
membrane limited to the bones of the arm, while in the species with
small hind-legs it may have attained even as great a development as in
Bats, though there is no reason for suspecting that it extended to
the tail. A Pterodactyle cannot be supposed to have hung itself up by
the hind-legs as does a Bat, because the hind-claws appear invariably
to be directed forward. A Bat walks upon four legs with considerable
elegance and speed; the wing is folded in, close to the side, so as to
be scarcely noticed; and the outer claw is free to climb with. There
can be little doubt but that Pterodactyles walked in a similar way. The
thickened mammilate knob at the proximal end of the first phalange is
well calculated for contact with the ground. And if it were supposed
that the large wing-metacarpal bone were only used to support the wing,
and the small metacarpals only used to support the claws by which
the creature has sometimes been pictured suspending itself, it would
be difficult to believe that the forces of pressure and tension in
flying so exactly corresponded to the forces manifested in suspension
as to cause the large and the small metacarpals invariably to attain
the same length. A correspondence of this kind may be presumed to
indicate a correspondence in function; and since the animal did not
fly by means of its claws, the inference is that it walked by means of
the metacarpal bones. In no other way could the bones have been used
equally. The avian ilium would suggest a probability that they also at
times stood erect like birds, from which position they could with more
ease expand their wings; nor is such an idea opposed by the resemblance
of some bones of the hind-limb to what obtains in birds, and of the
neck of the femur to what is seen in mammals of great power in the
hind-legs.

That they lived exclusively upon land and in air is improbable,
considering the circumstances under which their remains are found.
It is likely that they haunted the sea-shores, and, while sometimes
rowing themselves over the water with their powerful wings, used the
wing-membrane as does the Bat to enclose their prey and bring it to the
mouth. But the superior development of the pneumatic foramina suggest
that their activity was greater than in ordinary sea-birds.

The large Cambridge Pterodactyles probably pursued a more substantial
prey than dragon-flies. Their teeth are well suited for fish, but
probably fowl and small mammal, and even fruits, made a variety in
their food. As the lord of the cliff, it may be presumed to have taken
toll of all animals that could be conquered with tooth and nail. From
its brain it might be regarded as an intelligent animal. The jaws
present indications of having been sheathed with a horny covering, and
some of the species show a rugose anterior termination of the snout
suggestive of fleshy lips like those of the Bat, and which may have
been similarly used to stretch and clean the wing-membrane.

The high temperature, coupled with the sub-aerial life, are opposed to
the idea of the animal having been naked. The undisturbed condition of
the skeleton and some points of structure are opposed to the idea of
their having had large feathers. The absence of such remains does not
favour the hypothesis of their having been covered with scales, though
in the legs of birds a scaly covering is met with. I should anticipate
for them a filamentous downy feather, or hair, like a Bat's. The Bat
combs its hair with its claws, and the Ornithosaurians may have used
their claws in a similar way.

They cannot be supposed to have been gregarious, from the large number
of species relatively to specimens. The reproduction may have been
much the same as in birds; and the young were probably reared with
affectionate care[X].

[Footnote X: Mr Carruthers has shown me crushed Turtle-like eggs from
the Stonesfield slate, which in the external pitting of the egg-shell
are not so different from some birds as to preclude a suspicion that
they might possibly be Ornithosaurian.]

       *       *       *       *       *

_The following notes indicate structures in perfect specimens from the
Lithographic slate which supplement the fragmentary remains from the
Cambridge Greensand_[Y].

[Footnote Y: The German animals form different family groups. And
it cannot be inferred that the structures seen in them pertained to
Cambridge specimens.]

In the head, Cambridge specimens show no trace of the parts which are
between the brain-cavity and the fore-part of the jaw. The form and
condition of the orbits, nares, and of the space between them, vary
in German specimens. Some Birds and certain Ruminants, such as deer,
the giraffe, &c., have an interspace between the orbits and nares
corresponding to that in some Pterodactyles, but no such perforation
is found in living reptiles. In mammals it appears to be surrounded
by the frontal, nasal, lachrymal, and often by the maxillary bone.
In birds the bones appear to be the lachrymal, nasal, maxillary and
premaxillary, as is the case with Pterodactyles, except that the nasal
bones would seem sometimes to be excluded. The chief peculiarity of
the Pterodactyle skull in this region is made by the malar bone (and,
according to some authors, the maxillary also) sending up a process to
meet the lachrymal. This is not seen in birds, but is characteristic of
many mammals and reptiles.

The premaxillary bone is single, as in birds and Iguana; but it appears
to attain as great a development as in birds, and to occupy the portion
of the jaw which among reptiles and mammals is made by the maxillary
bone. Owing to the great development of the premaxillary bones, the
exterior nares are placed far back toward the middle of the skull as in
birds, and not near the tip of the snout as in living reptiles and most
mammals.

The orbits in Pterodactyles are surrounded with bone, as is commonly
the case with mammals and reptiles. Among birds a complete orbit
is seen among the parrots, in which it is completed below by a
prolongation of the outer posterior corner of the frontal, which would
correspond to the post-frontal bone, and by the lachrymal bone. Thus
the malar bone, which in most mammals and reptiles forms an important
part of the lower margin of the orbit, is in birds entirely excluded.
In Pterodactyles the malar bone is placed between the lachrymal and the
post-frontal process of the frontal bone.

The quadrate bone in German Pterodactyles, instead of being vertical
as in birds, stretches obliquely forward below the malar bone, so that
the articulation for the lower jaw is brought forward to be under the
middle of the orbit. In _Pterodactylus Kochi_ and in other species
there appears to be a process, or small separate triradiate bone,
comparable to a diminished lacertian post-frontal, and homologous
with the post-frontal process of the parrots. Its upper branch meets
the frontal. In some genera the front appears to meet the malar. The
lower branch goes to the front of the quadrate bone, and the backward
branch goes to the squamosal immediately above the articulation for
the quadrate bone. Thus it is a post-frontal bone resembling that
of the Iguana, but modified and adapted to a cranium like that of a
bird. Its form and size in the different genera are very variable. No
similar development is seen among mammals, where the post-frontals have
probably ceased to exist. It is a carious point of resemblance, but
from the other resemblances to Iguana being so few it is robbed of much
of its force as a mark of affinity, and becomes of interest chiefly as
an evidence of independent persistence of structures.

The pterygoid and palatine bones approximate to those of bird and
lizard in Pterodactylus crassirostris. And the bones in Pterodactylus
suevicus, which Quenstedt names vomera, should rather have been named
palatines. There is a bone in Goldfuss' specimen, between the malar and
palatine, which he identifies with the transverse bone, but it is not
seen in any other specimen.

The ribs sometimes appear to articulate by single heads, but in P.
crassirostris they are apparently articulated as in the Crocodile.
Some species show abdominal ribs like those of some reptiles; but the
segments of the mammalian sternum and abdominal ribs are to be regarded
as homologous structures. The vertebræ offer considerable variety in
size and shape, but the greatest variation in number is seen in the
tail, which is sometimes stiff and long, and sometimes short. The
pelvic bones show a large amount of variation in different genera,
often appearing to be crocodilian, sometimes lacertian, sometimes
mammalian. In the aim the humerus is variable in the length of the
radial crest, and the metacarpus also varies in length.

When the external similarity of the skeletons of birds is borne
in mind, it is impossible, without disregard of classification
altogether, to place animals differing so widely as do the different
Ornithosaurians in the few genera in which they are at present packed.




CLASSIFICATION.


The orders of Ornithosaurians may be established hereafter. Under the
name Pterosauria, Prof. Owen founded one order which has for its type
the Pterodactylus longirostris.

Von Meyer proposed to separate this order into two groups, one with
two phalanges in the wing-finger, of which Ornithopterus is the only
example, forming his Diathri; while the other group, Tetrathri,
or those "with four fingers, comprised all other Pterosaurians.
The Tetrathri he again subdivided, following out, as he states,
the suggestion of Munster and Goldfuss, into _Dentirostres_ or
such Pterodactyles as have the jaws furnished with teeth to their
anterior termination; and the _Subulirostres_, or such as want teeth
at the extremities of the jaws. To the former group he left the name
Pterodactylus, and to the latter was given the name Rhamphorhynchus.
Von Meyer says that he might easily have made a few more species, as
will be evident to those who inspect his plates, but he "believes
that the students of living animals go too far in their tendency to
subdivide:" a fancy that, if indulged in by Palæontologists, would have
the effect of restoring the old Linnæan groups; and a complaint which,
although often heard, has usually come from those who do not readily
discern and appraise classificational characters. In Palæontology
genera are sometimes co-extensive with orders, while species often mean
genera. It may be wearisome to the collector to be lured on to follow
the devious ways of a science, but Palæontology, the source whence
the mysteries of existing nature must unravel their meaning, is the
handmaid of all nature's truths which have been buried in evolving the
existing creation; and a duty devolves upon Palæontologists to make the
past an inseparable part of the present, by applying to the two the
same scientific method.

A year previous to the formation of Owen's Pterosauria, Bonaparte named
the Order Ornithosaurii, and divided it into a family--Pterodactylæ,
and a sub-family Pterodactylinæ.

Fitzinger (_Systema Reptilium_, 1843) also used the same ordinal name,
and recognized three genera--

_Pachyrhamphus_, of which the type is Pterodactylus crassirostris
(Gold.).

_Pterodactylus_, with the type P. longirostris (Cuv.).

And _Ornithocephalus_, with the type O. brevirostris (Sömm.).

These and other attempts at classification all endeavour to subdivide
Ornithosaurians by the head or by the tail. Other characters for
primary divisions may be obtained from the pelvis.

In the majority of German Pterodactyles the ilium extends for a long
distance in front of the os pubis, and only for a very short distance
behind the large ischium; and the small pubis from its anterior margin
gives attachment to a large prepubic bone, which resembles in form
the os pubis of the Crocodile[Z], and is unlike that of the Monotreme.
These appear to include the long-legged animals with short tails, at
present called Pterodactyles, and form a well-marked family or order.

[Footnote Z: Prof. Haughton, from a study of the bones and muscles,
came to the conclusion that the pubic bones of Crocodiles are the
marsupial bones.]

Another kind of pelvis is that in which the ilium extends a short
way in front of the acetabulum, in which the pelvic bones inclose a
much larger space. These include the Cambridge Ornithosaurians, the
Rhamphorhynchus, and the Dimorphodon, and form another well-marked
family.

These long-tailed Pterodactyles subdivide into three
sub-families--Rhamphorhynchæ, Dimorphodontæ, and Ornithocheiræ. The
four families may then be defined thus:

  _Pterodactylæ_. Tail short. Hind-legs long. Ilium narrow, extending
    far anterior to the acetabulum; ischium extending behind the
    acetabulum. Epipubic bones ficiform. Head with the middle holes
    large, often confluent with the exterior nares. Jaws toothed to the
    anterior extremity.

  _Rhamphorhynchæ_. Tail long and stiff. Hind-legs short. Pubis and
    ischium small, oblique to ilium, which extends less far anteriorly
    than in Pterodactylæ. Epipubic bones narrow and bent; they unite
    mesially and form a three-sided bow in front of the pelvis. Head
    with the middle holes and nares both small. Jaws never toothed to
    the anterior extremity.

  _Dimorphodontæ_. Tail long and stiff. Hind-legs long. Pubis and
    ischium forming an expanded sheet of bone at right angles with the
    narrow ilium, which extends as far behind as in front [prepubic
    bones triangular (?) attached by the apex of the triangle]. Head
    with the nares and middle holes large. Quadrate bone large. Jaws
    with large teeth at the extremities, and small teeth behind. No
    sacrum.

  _Ornithocheiræ_. Tail long and flexible. Hind-legs short. Pelvis as
    in Dimorphodontæ. [Epipubic bones with a small attachment, form
    unknown.] Head with the quadrate bone small. Sacrum of not fewer
    than three vertebræ.

In the Pterodactylæ the genera are--

  _Pterodactylus_ (Cuvier), in which the exterior nares are at the
    sides of the face, very large, and only partially, if at all,
    separated by bone from the small middle hole of the head. The head
    is elongated. The neck is long. Among others, it includes the
    species P. longirostris, P. Kochi, P. scolopaciceps, P. longicollum.

  _Ornithocephalus_ (Sömmerring), in which the anterior nares are
    entirely separated from the middle holes of the head, both being
    small, and the latter exceedingly small. The head is short The
    neck is short. The large ischium appears to be excluded from the
    acetabulum, and the ilium appears to extend less far forward than
    in Pterodactylus[AA].

[Footnote AA: So far as can be judged from figures, it appears to have
but three bones in the wing-finger: what Cuvier regarded as a terminal
and fourth joint, the bone _n_, Pl. XXIII. fig. 7, _Oss. Foss._,
appearing to me to be the fibula of the tibia marked _e_. _s_ in the
same figure would be the terminal phalange, and _r_ the first phalange,
as may be proved by measuring them with those of the other hand,
so that a phalange is missing from between them. Both the terminal
phalanges appear to be hooked at the termination. Goldfuss figures
the phalanges so as to make the bone which appears to be fibula in
Sömmerring and Cuvier look like a fourth phalange.]

  _Pachyrhamphus_ (Fitzinger). The nares are entirely separated from
    the middle holes of the head; both are large. The head is thick
    and massive. The prepubic bones meet mesially. No evidence of
    the number of phalanges in the wing-finger. The quadrate bone
    is massive, but has small attachment to the skull. Two sacral
    vertebræ. Wing-metacarpal very short. The type is P. crassirostris
    (Goldfuss).

  _Cycnorhamphus_ (Seeley). Nares very small, looking upward from
    a swan-like beak. The middle hole of the skull very large and
    elongated and lateral. Neck long. Wing-metacarpal long. Four joints
    in the wing-finger. Ilium widening in front. Epipubic bones meeting
    mesially. The type is Pterodactylus suevicus (Quenstedt).

In the Rhamphorhynchæ at present there appears to be but one genus
known:

  Rhamphorhynchus (von Meyer). The nares and middle holes are both
    small, ovate, of nearly equal size, and close together at the side
    of the head in front of the orbit.

In the Dimorphodontæ the only genus is

  _Dimorphodon_ (Owen). It has the nares enormously large. The middle
    holes are also large.

In the Ornithocheiræ the genus is

  _Ornithocheirus_ (Seeley), in which teeth are prolonged anterior to
    the muzzle, and the palate has a longitudinal ridge.

With the osteological illustrations of the Ornithosauria are arranged
some premaxillary bones, which show varieties of form of the snout.
These variations of shape serve easily to indicate different species.
And the following memoranda from those specimens and other specimens
in the drawers form a synopsis of the species of the Cambridge genera,
which may hereafter be fully elucidated from the copious materials in
the series of associated remains.


  I.

  Ornithocheirus Sedgwicki (Owen).

  Case. Comp. Tablet. Specimen.
   =J=   _c_    13       2

The fragment is 2-7/8ths inches long, with the elliptical teeth
opposite to each other, 6 on a side on the palate, and one pair in
front. The first three teeth are large; behind these the teeth are
about half the size. The palate is gently convex, with a faint median
ridge, and measures from side to side over the fourth and subsequent
sockets 13/16ths of an inch. The height of the jaw at the fourth socket
1-1/4 inch. The sides converge to an acute rounded rostral keel. The
jaws appear to have been long. The anterior termination is vascular.

The rostral keel figured by Owen Pl. I, fig. 1 _d_, in the 1st Supt.
_Cret. Reptiles_, is not square as represented there, but rounded;
the sides converge more acutely, and at the ridge the keel is not
half so wide as the figure makes it. The enormous size of the third
tooth-socket is partly due to the cracked bone having absorbed
more phosphate of lime than it could hold, and extended the cracks
to fissures. The type specimen shows that there was another pair
of sockets in front of, but quite close to, those which appear to
terminate the lower jaw.


  II.

  Ornithocheirus Cuvieri (Bowerbank).

  Case. Comp. Tablet. Specimen.
   =J=   _c_    15      1-3

A portion of a premaxillary bone fractured at both ends, and two inches
long, corresponds with Dr Bowerbank's fossil figured Pl. XXVII. fig. 1,
3, 4, in the Palæontographical volume for 1851. The palate is just as
wide; the median ridge, the same; the teeth the same in shape and as
far apart. The jaw is of the same depth, but does not deepen so rapidly
behind. The only other difference is that the sockets of the teeth are
less prominent on the sides, and appear to look more directly down.

The ridge in which the converging sides meet is well rounded in a
dentary bone which may have pertained to this species. In the space
of two inches and a quarter are 5 teeth, the posterior four extending
over two inches, the other pair being in front. The palatal surface is
3/4 of an inch broad behind the third tooth, and rather more than 5/8
of an inch broad behind the fourth tooth. The length of the 4th or of
the 5th sockets is two-thirds that of the second or third. In front of
the 5th tooth, the jaw is an inch deep, and it tapers in a curve to
the anterior end. The teeth behind the third have interspaces greater
than the length of the sockets; that between the 4th and 5th being 3/8
of an inch, while the socket only measures a quarter of an inch long.
Behind the 2nd socket commences the palatal groove, broad in fronts but
narrowing behind; and its sides instead of diverging as in the type,
are concave so as to form a channel like a straightened _Siliquaria_
shell. The halves of the palate bevel off so as to make a right angle
with each other, and greater angles with the flat sides.


  III.

  Ornithocheirus machærorhynchus (Seeley).

  Case. Comp. Tablet. Specimen.
   =J=   _c6_   35       1

Dentary bone. Broken at both ends, and wanting all its teeth, this
interesting fossil shows the suture where its whole length rests on the
angular bone which almost reached to the termination of the beak, quite
unlike what is seen in any German Pterodactyle.

It is a narrow mandible, less than three quarters of an inch wide, with
the alveolar margins parallel. The palatal surface 1-1/2 inch long,
is divided into 3 equal strips; the middle one being a deep glossal
groove, slightly narrowing in front, and deepening behind, made by two
inclined flat surfaces. The lateral strips are horizontal behind, and
in front slope a little outward. The tooth-sockets are oval, directed
outward, and as long as the interspaces, though these seem to get
longer behind. In an inch and a quarter there are four teeth. Below
the teeth, the sides of the jaw are compressed: though nearly parallel
at the hinder fracture, the flattened surfaces approximate in front
till they meet in a sharp keel, which appears to make an acute angle
of about 45° with the palate; and below, where the jaw is an inch deep
extends for half an inch in front of the suture with the angular bone:
this suture is straight and irregularly concave, and in an inch and a
quarter approximates to within 5/8ths of an inch of the palate.


  IV.

  Ornithocheirus tenuirostris (Seeley).

  Case. Comp. Tablet. Specimen.
   =J=   _c2_   12       1

Middle part of a premaxillary bone fractured behind and in front,
slightly distorted by compression; it is 2-1/8th inches long, and
nearly resembles _O. compressirostris_ (Owen). The palate is about
1/2 an inch wide in front, and 5/8ths of an inch wide behind; it is
compressed mesially into a strong angular keel, between which and
the teeth there is a shallow groove on each side. The groove dies
away behind, and the converging parts of the keel occupy the whole
space between the teeth. The teeth-sockets are small, elliptical, not
opposite to each other, and placed along a distinct flattened tooth
area, which looks downward and outward and separates the palate from
the side of the jaw. The first pair of sockets preserved are almost
3/16ths of an inch long and 1/16th of an inch wide. The interspace
between that tooth and the next tooth behind is 7/16 of an inch.
Separated by similar interspaces, behind these on one side are two
sockets, and on the other side one socket. The sides are flattened in
front, and convex behind, (making the section of the jaw lanceolate);
they are compressed and round into a narrow rostral keel. The height
from the palatal ridge to the rostral keel in front is 11/16ths of an
inch; behind it is fractured, but the height was probably 14/16ths of
an inch.

The palatal keel, distance of the teeth, and proportions of the jaw,
distinguish it from O. compressirostris (Owen).



  V.

  Ornithocheirus Oweni (Seeley).

  Case. Comp. Tablet.
   =J=   _c_    20

The small piece of premaxillary on which this species is founded
indicates a small animal, and nearly resembles the jaw of _O. microdon_.

It is scarcely an inch long; nearly 9/16ths inch high behind, and
nearly 7/16ths of an inch high in front, so that it tapers very
rapidly, and could scarcely have been an inch longer in front.

The nose is well rounded, but the sides are a little concave, and
become well pinched in in the middle, behind, showing the near approach
as I think to the nostril.

The palate half an inch broad, is divided into two concave channels by
the strong and sharp median ridge, which projects below the alveolar
margins. The dental margins are not rounded as in _C. microdon_, but
flattened, making more than a right angle with both the outer side-wall
and palate. The interspaces between the teeth are rough, looking as
though they had supported minute teeth. The alveolar margin is a
tenth of an inch wide; along it are the perfectly circular sockets, a
sixteenth of an inch in diameter. There are 3 sockets between 5/8 of an
inch, so that they are separated by 3 times their diameter. The palate
is obliquely impressed with blood-vessels running forward to the teeth
from the median ridge.

The points in which this jaw differs from that of _O. microdon_ are
that in this species the teeth are circular instead of being oval; that
the interspaces here are as long as in that species, though this jaw
is only two-thirds the width; that instead of having a sharp keel on
the upper surface, this has a well rounded roof. That though the jaw
is scarcely higher than it is wide, it shows strong furrows running up
to the nares, while in _O. microdon_, though the proportions are the
same, the sides are perfectly flat without trace of pinching in, while
the line of the nasal opening is indicated by a faint furrow running
all along the jaw. And lastly it differs in size, which, where the
sutures are lost, may be important in discriminating forms.


  VI.

  Ornithocheirus microdon (Seeley).

  Case. Comp. Tablet. Specimen.
   =J=   _c_    29      1-2

Premaxillary bone. The fossil is nearly 1-3/4ths inch long, and at the
proximal end, where it is less than 3/4ths of an inch high, has flat
sides, which converge to form a keel which is depressed anteriorly
and rounded so that where fractured in front the bone is 7/16ths of
an inch deep. The palatal surface contains two wide concave channels,
between which descends a sharp median ridge, which behind becomes more
prominent than the alveolar border.

The palate is 5/8ths of an inch wide. The alveolar margins are
compressed and rounded. The small tooth-sockets are oval, and four are
contained in 1-1/8th inch; they look downward.

There is a small tip of a jaw associated with this fossil, which is so
like that it might be part of the bone broken off before fossilization.
It corresponds in every way except that the teeth are closer. In this
terminal lanceolate fragment there are in 5/8ths of an inch four teeth.
The snout is terminated by two, which are close together.


  VII.

  Ornithocheirus Huxleyi (Seeley).

The only specimen of this species yet known is the greater part of a
dentary bone contained in the Museum of the Geological Survey. An inch
and 1/4 long and 3/4ths of an inch wide, it is less than half an inch
deep: the sides slowly converge towards the front, and it appears to
have had an obtusely lanceolate beak. The under surface is convex, too
inflated for trace of a keel, and tapers to the end of the beak, which,
with the left alveolar margin is abraded. The palatal surface is smooth
at its front end, but two diverging ridges soon arise and form the
boundary of a posteriorly deepening mesial channel, which is a quarter
of an inch wide at the fracture. These ridges too, which are parallel
with the compressed and rounded alveolar margins, convert the lateral
spaces into shallow channels. The right side shows the sockets of 3
small oval teeth separated by interspaces wider than teeth. A tooth and
two interspaces measure 7/16ths of an inch.

The only cretaceous Pterodactyle which this at all resembles is _O.
microdon_, but the palate is wider than in that species; the sides
converge towards each other more rapidly, as though it belonged to a
species with a shorter snout.

I am indebted to Prof. Huxley for the opportunity of making a notice of
this species.


  VIII.

  Ornithocheirus oxyrhinus (Seeley).

  Case. Comp. Tablet. Specimen.
   =J=   _c2_   13       1

This well-marked species is a portion of a premaxillary bone 1-1/4 inch
long, fractured behind and in front. The palate is half an inch wide;
its two halves are inclined to each other at a considerable angle, and
where they meet form a more prominent keel. The tooth-sockets look more
outward than downward, are nearly circular, separated by interspaces
as long as the sockets; three sockets and two interspaces measure one
inch. The jaw is about 5/8ths of an inch high in front, and about
1/16th of an inch higher behind. The sides are flat and converge like
the sides of a wedge to a sharp rostral keel.


  IX.

  Ornithocheirus xyphorhynchus (Seeley).

I have seen but one example of this form. It has lost much of the outer
layer of bone, and shows on the sides impressions like tooth-marks from
an eater of Pterodactyles. A groove which has some appearance of being
due to fracture traverses each side, but the specimen is symmetrical,
and has its characters in no way changed by the accident.

It is a portion of a lower jaw of a long-beaked Pterodactyle of the
_O. Sedgwicki_ type, with parallel sides, and the rounded basal ridge
nearly parallel with the palate.

The fragment is two inches long, showing four large and obliquely set
sockets in If inch. The tooth-sockets are on the outer two-thirds of
the palate, and looked forward, upward, and outward The interspaces
each measure 5/16ths of an inch.

Each half of the palatal surface which is 5/16 of an inch wide,
inclines to the other half at a right angle, being parted by a narrow
groove; the diameter of the jaw is half an inch.

The depth of the jaw is 5/8ths of an inch in front, and 3/4ths of an
inch behind. The sides are flat and approximate below to a sharp keel.
This species is one of many in the collection of W. Reed, Esq. of
York, kindly placed in my hands for the elucidation of those in the
Woodwardian Museum.


  X.

  Ornithocheirus Fittoni (Owen).

  Case. Comp. Tablet. Specimen.
    =J=  _c_    14      1, 2

The fragment is 1-1/2 inch long, with two large elliptical
tooth-sockets on each side of the flattened palate, and one pair in
front. The third socket is separated from the fourth by a considerable
interspace. Between the third sockets arises the median palatal ridge,
and from the inner margin of each socket a lateral ridge appears to be
continued. Behind the third socket the jaw measures 11/16ths of an inch
from side to side, and 10/16ths of an inch high. The sides converge
and round convexly into each other. The jaws appear to have been long;
It is only known by upper jaws. The type specimen shows the socket of
another tooth in front of the last one figured by Prof. Owen. It is
directed outward at a greater angle, and separated from the hinder one
by a wall not 1/16th of an inch thick, and the teeth of this pair must
have been parted from each other by a film equally thin. There is no
truncation of the snout as in _O. Woodwardi_.

Another specimen shows some variations. This fragment of a premaxillary
bone is fractured through the third pair of tooth-sockets in front
and through the seventh pair behind. It is about 2-1/8th inches
long; the palate is 11/16ths of an inch wide behind the great tooth,
and maintains the same width. The jaw is 11/16ths of an inch high
behind, and 10/16ths high in front. The sides are gently convex, and
imperceptibly unite to form the well-rounded depressed mesial ridge of
the beak. From the front of the third to the back of the fifth socket
measures 1-3/8ths inch. The sockets are ovate, rather smaller, and
closer together than in the type of _O. Fittoni_; margins elevated.
The variations from types are so many, and often so considerable, as
to suggest the idea that the fossil groups called species may in the
living animals have often been genera.

In all the specimens the end of the palate is a little reflected upward.


  XI.

  _Ornithocheirus dentatus_ (Seeley).

  Case. Comp. Series. Specimen.
   =J=   _c1_   9        1

A fragment of premaxillary bone two inches long, fractured behind the
socket for the seventh tooth. It most nearly resembles _O. Sedgwicki_
and _O. Cuvieri_. Behind the second tooth the palate is 1/2 an inch
wide; behind the sixth socket it is 5/8ths of an inch wide; the
distance between these points is nearly 1-1/2 inch. The palate is
flattened, with a sharp slight mesial keel and a wide concave channel
on each side which dies away in front. The first pair of teeth are in
front of the snout, rather small, and look forward. In this specimen
the large third tooth is not developed on the left side. The second and
third sockets are large and close together; the succeeding teeth are
parted from each other by interspaces equal to their own diameter. They
are gibbously elliptical. The sides of the jaw are gently convex from
above downward; they round into each other to form a narrow rostral
keel. Behind the second socket the jaw is 1/2 an inch high; behind the
sixth it is nearly 7/8ths of an inch high.

The grooved and relatively wider palate, and the relatively smaller
teeth, abundantly distinguish this species from _O. Sedgwicki_ (Owen).

The smaller, more circular teeth, placed closer together, distinguish
it from _O. Cuvieri_ (Bowerbank).


  XII.

  Ornithocheirus scaphorynchus (Seeley).

  Case. Comp. Tablet.
   =J=   _c_    22

This fragment of premaxillary bone is 1-1/2 inch long. The palate is
1/2 an inch wide behind, and the jaw is rather more than 1/2 an inch
high; behind the second tooth it is nearly 5/8ths of an inch high. The
sides converge superiorly to form a well-rounded keel. The palate is
flattened, with a slightly elevated blunt median keel. There appears to
be a pair of small teeth in front of the snout as usual, and six on the
palate, with an indication of another at the posterior fracture. The
teeth are of moderate size and almost circular. In the form of the bone
it is readily distinguished from all the species enumerated.


  XIII.

  Ornithocheirus platystomus (Seeley).

  Case. Comp. Series. Specimen.
   =J=   _c6_   32       1

An ill-preserved fragment fractured in front and behind, yet
indicating a distinct species. The palate is flat, with the faintest
median ridge, and the sides are flat and round into a narrow
rostral keel, which in front approximates rapidly towards the
palate. The first pair of sockets are missing; what appears to be
the second pair are about 1/8th of an inch long, separated from the
pair behind by an interspace of 1/4th of an inch. These are ovate
and less than 1/4th of an inch long, and separated from the next
pair by an interspace of not less than 1/4th of an inch. The height
of the jaw over the first pair of sockets preserved is 9/16ths of an
inch; over the second pair it is 14/16ths of an inch; the space
between these points is 9/16ths of an inch. Behind the second pair
of teeth the palate is nearly 5/8ths of an inch wide.

The only species which it resembles is _O. brachyrhinus_, but
differs from that in the flatter, narrower palate, which makes a
greater angle with the rostral keel, and in the smaller teeth,
which are separated by wider interspaces.


  XIV.

  Ornithocheirus nasutus (Seeley).

  Case. Comp. Series. Specimen.
   =J=   _c2_   11       1

A fragment of a premaxillary bone 6 inches long. It somewhat
resembles _O. Cuvieri_ in the aspect of the palate, but the jaw
is more elongated, and expands from side to side at the anterior
end. The teeth are opposite to each other in front, but become
irregular after the sixth. The palate measures behind the second
pair of sockets 3/4ths of an inch, behind the third pair it is a sixteenth
of an inch wider, behind the ninth pair half an inch, and in the
last two inches it begins to widen again. A sharp keel arises
behind the second pair of sockets and becomes more prominent to
behind the tenth pair, when the channel which accompanies it on
each side seems to disappear. The first pair of teeth, which look
forward, is smaller than the second and third pairs; they are closer
together than those which follow. The third sockets are 7/8ths of
an inch from the tip of the snout. Then follow three smaller,
more circular teeth, which are separated from each other by interspaces
as long as the sockets. The back of the sixth sockets are
2-1/4 inches from the tip of the snout. Then follow two larger
more elliptical sockets; after which the sockets become smaller
and are separated by longer distances, that between the 10th and
11th pairs is nearly 3/4ths of an inch.

The height of the jaw behind the second pair of sockets is 5/8ths
of an inch, behind the sixth sockets 15/16ths, behind the tenth sockets
1-1/4 inch. In front, the nose has the aspect of being compressed
from above downward, and behind it is compressed from side to
side. The sides are flattened and round into a narrow rostral
ridge which is depressed at the anterior end.


  XV.

  Ornithocheirus polyodon (Seeley),

  Case. Comp. Tablet.
   =J=   _c_    21

This species is founded on the anterior end of a premaxillary bone;
in form not unlike _O. Fittoni_. It is 5/8ths of an inch wide; the
lateral margins approximate very slowly, and in front it appears to be
truncated. It is an inch and a quarter long, and in that space were
on each side six large round teeth, almost as close together as they
could be, five on the palate and a pair in front. The terminal two
are no wider apart than the rest, and point more forward. A moderate,
sharp, median ridge descends in the flattened palate, making its
lateral halves a little concave. The front termination of the palate is
slightly reflected upward. The jaw, which is 1/2 an inch deep behind,
tapers to its termination more rapidly than does _O. Fittoni_. The flat
sides similarly converge, and form a well-rounded ridge, which does not
get blunter in front. From their close approximation, it results that
the tooth-sockets are entirely above the palatal surface, so that they
are better seen from the side of the jaw than from the palate.

It is a clearly marked species, as well distinguished from _O. Fittoni_
by the closeness of its teeth, as _O. Sedgwicki_ is from _O. Cuvieri_.


  XVI.

  Ornithocheirus denticulatus (Seeley).

  Case. Comp. Series. Tablet.
   =J=   _c5_   28      1

This is a species which can only be confounded with O. polyodon. It
is a fragment of premaxillary bone 1-3/4 inch long, fractured through
the seventh socket. It differs from O. polyodon in having larger
teeth, which are wider apart, look more downward, have a narrower
palatal interspace between each pair, and a rostral keel, which is more
compressed from side to side behind and from above downward in front,
and makes a greater angle with the palate.

The sockets are more uniform in size and closer together than usual,
the second and third pairs being but slightly larger than the others;
all are broadly elliptical. The palatal keel becomes sharp and
prominent behind the fourth sockets. Behind the second pair of sockets
the height of the jaw is nearly 7/16ths of an inch, behind the fourth
sockets the height is 10/16ths of an inch; the distance between these
points is about 10/16ths of an inch.


  XVII.

  Ornithocheirus crassidens (Seeley).

  Case. Comp. Series. Tablet.
   =J=   _c1_   2       2

This is a fragment of a ?premaxillary bone, fractured behind through
the socket for the fourth tooth. It approximates to O. colorhinus,
but differs chiefly in the nose not extending in front of the first
pair of teeth; in there not being any lunate area above the first pair
of teeth; in there being but one tooth in front, which is relatively
large; in the socket for the fourth tooth being quite close to that for
the third tooth, and in the palatal sockets looking much more outward.
The nose also appears to be better rounded.

The fragment is 1-7/8 inch long. The second and third sockets, with
their interspace, measure 1-1/8 inch. On the opposite side the first
socket is intermediate in position between the first and second.

Though not likely, it is just possible that this might be the
premaxillary bone of O. eurygnathus.


  XVIII.

  Ornithocheirus brachyrhinus (Seeley).

  Case. Comp. Tablet.
   =J=   _c_    24

This fragment of a premaxillaiy bone is fractured behind the sockets
for the third pair of teeth. It is 1-1/8 inch long, and shows one pair
of small teeth in front and two pairs of large ovate teeth on the
palate. The first pair are divided from each other and from the second
pair by films of bone; and the second pair are separated from the
third by rather more than half the length, of the third socket. Behind
the third pair of sockets the palate is 5/8ths of an inch wide; it is
flattened, and has a blunt moderately elevated mesial ridge. Behind
the second pair of sockets the jaw is 5/8ths of an inch high; behind
the third pair of sockets it is 3/4ths of an inch high; the distance
between the places of measurement is 1/2 an inch. The sides are flat
and converge to a rounded nose. The jaw is rounded from side to side
in front, and the outline of the top of the nose rounds over the blunt
termination of the snout above the teeth on to the palate.

In the shortness of the nose it somewhat resembles the _?P. giganteus_
(Bowerbank), but the jaw attenuates less rapidly, is truncated, and has
larger teeth.


  XIX.

  Ornithocheirus enchorhynchus (Seeley).

  Case. Comp. Tablet.
   =J=   _c_    25

This species nearly resembles _O. brachyrhinus,_ from which it differs
in larger size, with a relatively wider palate, which is without a
keel, and in a larger front pair of teeth. It approximates towards
_O, colorhinus_, but is smaller, and wants the rugose lunate area
over the front pair of teeth characteristic of that species. There
are many varieties or species nearly related to this type, but from
their imperfect preservation and the small part of the head which they
represent, it is not possible to give descriptions of them.


  XX.

  Ornithocheirus eurygnathus (Seeley).

  Case. Comp. Series. Tablet.
   =J=   _c3_   16      1

A fragment of a ?dentary bone, fractured behind through the socket for
the third tooth. The sockets are nearly circular. It measures about an
inch long,, and behind the socket for the second tooth 1-3/4 inch high.
The sides of the jaw are gently concave from above downward, having
a pinched aspect and approximating; they round into a narrow rostral
ridge, which widens towards the tip of the snout and is truncated by
a small sub-circular [or sub-pentagonal] rugose area at right angles
with the part of the palate behind the first pair of sockets. The first
pair of sockets are nearly as large as the second, and from the steep
incline of the jaw look more than usually upward; they are 7/16ths of
an inch long, are separated from each other by an interspace of 6/16
ths, and from the second sockets by an interspace of more than 1/8th of
an inch, while the second socket is separated from the third by about
1/4th of an inch. The palatal space between the second pair is about
3/4ths of an inch.


  XXI.

  Ornithocheirus colorhinus (Seeley).

  Case. Comp. Tablet. Specimen.
   =J=   _c_    17      1, 2

Fragments of premaxillary bones. The largest portion is 2-1/2 inches
long, and is fractured behind the socket for the fourth tooth, and the
upper part of the nose is also broken away. The palate is flattened,
with the median part slightly convex. The sides of the jaw converge
upward, but not rapidly; in front they round into each other, but there
is a slight mesial depression. The front pair of teeth are large,
separated from each other and from the second pair by films of bone.
Above the first pair of sockets, so as to look downward and forward, is
an impressed lunate area 9/16ths of an inch wide and 5/16ths of an inch
high, to which a soft lip may have been attached. This area is in the
same plane with the first pair of teeth and at right angles with the
upper outline of the nose. The sockets of the first pair of teeth are a
little smaller than the second pair; they are both about half an inch
in diameter and nearly circular. An interspace of 3/16ths of an inch
separates the second socket from the third. The tooth is elliptical,
the socket being narrower and longer than that of the second. The
palatal interspace between the third pair is more than 3/4ths of an
inch. The interspace between the third and fourth sockets is about
3/8ths of an inch. The diameter of the nearly circular fourth socket is
1/4th of an inch.

The overhanging lunate lip space, with the size of the teeth and width
of the palate, abundantly distinguish this species.


  XXII.

  Ornithocheirus woodwardi (Owen).

  Case. Comp. Tablet. Specimen.
   =J=   _c_    18      1-4

I regard the fragment on which this species was founded as being the
terminal end, and not a section of a jaw; partly from the rounding of
the lateral surfaces to the front, and chiefly from the snapped off
teeth in the middle of the truncated anterior end, for they are smaller
than the pair behind them, and look forward at a greater angle, so that
the converging sockets of both pairs meet behind. These characters are
well shown in Mr Dinkel's excellent figure, Pl. II. fig. 3_a_. Second
Sup. Palæont. The palate is destroyed, and gives no clue to the bone
being either lower or upper.

Another specimen, rather smaller, shows the rostrum well rounded; the
front is truncated at right angles to it: there is the same rounding
of its lower part into the sides, and the stumps of the front pair of
teeth are visible though they are again worn level with the rugose
front of the snout.

But the finest fragment of this species is a rostral end, (perhaps of
the upper jaw) three inches long, two inches deep, and with the palate
as wide. It indicates 5 teeth on a side: the front pair small, 2nd and
3rd much larger, and two pairs behind, which are smaller. The palate
is flat, and attains its greatest width at the third tooth, behind
which it contracts noticeably. The third tooth is more than half an
inch in diameter, the fourth is 5/16ths of an inch long. The spaces
between teeth seem equal to the long diameter of the sockets, which
are oval and straight. The sides round into the front of the muzzle
more gradually in this specimen than in the others. An impressed line
runs along the median ridge of the upper surface. Just as the jaw gets
narrower behind, so the well-rounded upper surface becomes more acute
behind.

Behind the third socket the palate measures 1-7/8 inch from side to
side, and the jaw is there nearly 2 inches high.

This is the most massive Pterodactyle jaw known. In the recent state
it may have indicated a creature sufficiently distinguished from
those to which the smaller fossils belonged, but now the divergence of
characters is so slight as to be for zoological purposes of no value.

It is related to O. Fittoni; the chief points of difference being the
truncated muzzle, the compression behind the third tooth, the much
sharper (?) dorsal ridge, and the large size of the head.


  XXIII.

  Ornithocheirus capito (Seeley).

  Case. Comp. Series. Tablet.
   =J=   _c3_   14      1

A fragment of premaxillary bone, well distinguished from every other
specimen, except one in the collection of Mr Reed of York, which is
here named _O. Reedi_. It is a large head, with larger teeth than any
known species. The jaw is truncated in front, with a rugose vertical
area in front reaching 1-3/4 inch high from the palate, on which the
usual front pair of teeth are not seen. At the angle of this front area
with the palate is a large elliptical tooth 9/16ths of an inch wide,
and behind it, with an interspace of 3/16ths of an inch, is a socket
measuring 10/16ths of an inch in length; the next interspace is about
1/8th of an inch, and the next nearly circular socket is 5/16ths long;
then another interspace of 1/8th of an inch, and another and a smaller
tooth. The palate appears to have been channelled. The sides of the
jaw are flat, or slightly concave, and where fractured above, are 3
inches high. Above the rugose vertical area of the snout, is an area,
concave from back to front, reaching up to the rostral keel; it is flat
from side to side behind, and convex from side to side in front. So
much as is preserved measures 1-3/4 inch in length, and appears to be
relatively narrower than in O. Reedi.


  XXIV.

  Ornithocheirus Reedi (Seeley).

The anterior part of an upper jaw has flattened slightly concave sides,
which converge above so as to form boundaries of (1) a flat triangular
area which looks anteriorly, and of (2) an oblong area, traversed by
a mesial groove, which looks upward and forward and is concave from
back to front. In the lower half of the truncated triangular anterior
termination are the remains of the stumps of the two anterior teeth;
they are oval in outline, 9/16ths of an inch high, and 7/16ths of an
inch wide; they are parted by an interspace nearly 1/4 of an inch
wide, which becomes concave vertically as it rounds on to the palatal
surface. All the front triangular surface above the teeth is rough: its
entire height is about 1-1/4 inch, and is nearly as wide across the
base. The side rounds a little into the concave median upper surface,
and into the triangular front; so much as is preserved measures 2-1/2
inches high, and 1-3/8 inch long. The palatal surface, which is very
small and badly preserved, is 1-3/4 inch wide behind, but gives no
indication of further widening. On its outer border are seen two large
circular teeth 5/8ths of an inch in diameter; they are separated by a
median palatal interspace of 7/8ths of an inch. Where it is fractured
behind, the specimen shows the sockets of another pair of teeth behind
these, with an interspace of 1/4 of an inch in the antero-posterior
direction. The palate is convex.

The superior oblong area is concave in length as well as transversely.
It makes a great angle with the triangular front of which it is the
upward continuation; so much as is preserved extends 1-1/2 inch in
length; it is about 1/2 an inch wide.

I am indebted to W. Reed, Esq. of York, for the opportunity of making a
notice of this species, which closely resembles _O. capito_.

       *       *       *       *       *

  The species which follow were separated in the "Index to the
  Ornithosauria," &c. as a different genus. That proposal might
  still be sustained, for these massive truncated jaws are unlike
  the spear-shaped jaws of many of the species. And to the minds of
  some readers the forms already described will arrange themselves in
  groups which not improbably indicate genera. But a re-examination of
  the type _Pterodactylus simus_ (Owen) has convinced me that it is a
  _lower jaw_, and therefore it affords no evidence of the presence or
  absence of the peculiar front premaxillary teeth which characterize
  nearly all the Cretaceous species.


  XXV.

  Ornithocheirus simus (Owen).

  Case. Comp. Specimen.
    =J=  _c_  16

The palate is 2-3/4 inches long, and at the second pair of teeth
about 7/8ths of an inch wide. It is fractured at the end through
the fifth socket, and at the side along the palatal groove. The
first pair of teeth is smaller and closer together than the others.
The palatal interspace between the second pair is 3/8ths of an inch;
between the third pair, which are large teeth, it is 1/2 an inch.
The sockets are sub-circular, and are not separated from each
other by wider interspaces than their own length. In front is a
long triangular rugose area, convex from above downward, a distance
of 1-1/2 inch; and concave from side to side, a width above of
rather more than 1/2 an inch. Below this the flattened sides converge
to a blunt keel; where, fractured, the jaw is 2-1/2 inches deep.
There are several fragments of species allied to the last; one
has the triangular area in front very small, only half as high as
in the type and very narrow, for the sides are gently rounded
into it. It is marked by short longitudinal furrows, impressed
vessels I think, while in O. simus the surface is irregularly rough.
The first pair of teeth are much larger than in O. simus; they
are longer, more conical, and circular, and separated by as wide a
space as the second pair. There is not much to found a species on,
but as it appears to be quite distinct from O. simus, it is named
_O. Carteri_. Another fragment, with the area very long, is marked
_O. platyrhinus_. But a sufficiency of species has been indicated to
make known the Ornithosaurian fauna of the Cambridge Greensand.
And the detailed description of critical types and of the
other parts of the skeletons is beyond the general osteology of the
tribe, and will rather belong to a memoir in which this flock of
Pterodactyles will be restored to their living forms.

       *       *       *       *       *

  A fragment of the lower jaw of a large Ornithocheirus has been
  obtained from an outlier of the Upper Greensand at Rocken End in
  the Isle of Wight. It appears to indicate a distinct species. It is
  2-1/2 inches long, and shows three large teeth still preserved in
  their sockets. The extreme width outside the third pair of sockets
  is nearly 2 inches. The sides, which are slightly concave from above
  downward, converge so as to give the broken end a triangular outline.
  In front is a small sub-triangular area, deeply scored with vascular
  markings; below this the outline slopes obliquely backward, and the
  two sides there round convexly into each other. The first socket is
  7/16ths of an inch long, the tooth coarsely striated, and like the
  others elliptical; the interspace between the first and the second
  teeth is 5/16ths of an inch. The second tooth, probably immature, is
  an inch in length, smooth, and like the third traversed in front and
  behind by a slight lateral ridge; at the base it measures 5/16ths
  of an inch from front to back. The third tooth is rather less than
  5/8ths of an inch from front to back. The interspace between the
  first and second _sockets_, which the teeth do not entirely fill,
  is more than 1/4 of an inch. The posterior margin of each socket is
  elevated into a sort of collar.




APPENDIX.

  _Enumeration of some of the principal writings on the Ornithosauria
    (selected chiefly from Von Meyer's Reptilien aus dem
    Lithographischen Schiefer), with references to the shelves in the
    Cambridge University Library, where the books may be consulted._

  Agassiz (Louis).--Memoires Soc. Nat. Neuchâtel, Vol. 1, p. 19,
    _paragraph notice in a memoir_, "Résumé des travaux de la section
    d'histoire naturelle, et de celle des sciences medicales
    pendant l'année, 1833"                                       B. 3. 66.

    A briefer notice in a paper, "A Period in the History of our
      Planet," in Edinburgh New Phil. Journal, 1843, Vol. 35,
      p. 9, quoted by Von Meyer                            XXVIII. 36. 65.

  de Blainville (D.).--Osteographie; Palæotherium, p. 9 (Vol. 2),
    quoted by v. Meyer                                           AF. 5. 9.

  Bonaparte (C. L.).--Nuovi Annali delle Scienze Naturali Bologna[1],
    Vol. 1, 1838, p. 391; Vol. 4, 1840, 24 Sept. p. 91.

  Blumenbach.--Manuel d'Histoire naturelle, éd. 1803, Vol. 2,
    p. 408                                                      B. 12. 20.

    (Vergleichende Anatomie, 1805, p. 75), § 44, Translation,
      1807                                                     Tt. 18. 51.

    Handbuch der Naturgeschichte, 1825, p. 620                  Yy. 39. 6.

  Burmeister.--Gesellsch. zu Halle, Vol. 3, Part 2, 1855;
    Viertel-jahrsbericht, 28 April, p. 11                     XXVI. 50. 2.

  Collini.--Acta Acad. Theod. Palat. 1784, Vol. 5,
    p. 58, pl. 1.                                               17. 5. 34.

  Cuvier.--Ossemens fossiles, Vol. 5, Pt. 2, p. 359, ed. 1824, pl. 23.
                                                               VII. 1. 36.
    Annales du Museum, 1809, Vol. 13, p. 424                   B. 42. 13.
    Règne Animal, ed. 1850, Vol. Rept. p. 62.               XVIII. 15. 15.

  Dumeril et Bibron.--Erpétologie générale, Vol. 4, p. 549.     B. 37. 33.

  Fischer.--Bibliotheca Palæontologica, Moscow, 1834, p. 163.  LR. 15. 58.

  Fitzinger.--Systema Reptilium[1], 1843, p. 35.

  Fraas.--Württemb. naturw. Jahreshefte, XI. 1855, p. 102.  XIII. 24. 25.

  Giebel.--Jahresbericht des naturwiss. Vereins zu Halle[1], 1849-50.
    Fauna der Vorwelt, 1847 (Vögel und Amphib. p. 89).          B. 46. 17.
    Allgemeine Palæontologie[1], 1852, p. 231.

  Goldfuss.--Nova Acta Leopold., XV. Part 1, p. 63, pl. 7-10.   23. 4. 63.


  Van der Hoeven.--Verslagen en Mededeelingen van het K,
    Nederl. Institut over den Jare, 1846, p. 430.              23. 6. 136.

  Merk.--Bald. Medic. Journ. Stück. 1787, Vol. 4, p. 74.    XVIII. 23. 10.

  H. von Meyer.--Reptilien aus dem Lithograph. Schiefer, 1859
     (Fauna der Vorwelt)                                        KK. 1. 55.
    Nova Acta Leopold., XV. Part 2, 1831, p. 198, pl. 60        23. 4. 64.
    Palæologica, 1832, pp. 115, 228                             X. 20. 39.
    Jahrb. für Mineral. 1837, p. 316                         XIII. 14. 32.
                        1838, pp. 415, 667                   XIII. 14. 33.
                        1843, p. 583                         XIII. 14. 38.
    Palæontographica, Vol. 1, p. 1846                           B. 40. 53.
    Jahrb. für Mineral. 1854, p. 51                          XIII. 14. 50.
                        1855, p. 328                         XIII. 14. 61.
                        1856, p. 826                         XIII. 14. 52.
                        1857, p. 535                         XIII. 14. 53.
                        1858, p. 62                          XIII. 14. 62.

  Von Munster.--Jahrb. für Mineral. 1832, p. 412             XIII. 14. 27.
    Nova Acad. Leopold., XV. Part 1, p. 49, pl. 6               23. 4. 63.
    Jahrb. für Mineral. 1836, p. 580                         XIII. 14. 31.
    Beiträge zur Petrefaktenkunde, i.; p. 83, 1839           XIII. 11. 49.
    Jahrb. für Mineral. 1839, p. 677                         XIII. 14. 34.
                         1842, p. 35                         XIII. 14. 37.

  A. Oppel.--Württemb. naturw. Jahreshefte, XII. 1856, p. 326.
                                                             XIII. 24. 25.
    Württemb. naturw. Jahreshefte, XIV. 1858, p. 55          XIII. 24. 26.

  Oken.--Isis, 1818, p. 246, pl. 4                             XXII. 5. 2.
               1819, p. 1788                                   XXII. 5. 3.

  Quenstedt.--Jahrb. für Mineral. 1854, p. 570               XIII. 14. 50.
    Ueber Pterodactylus Suevicus[1], 4to. 1855.
    Sonst und Jetzt[1], 1856, p. 130.
    Württemb. naturw. Jahreshefte, XIII. 1857, p. 41; XIV. 1858,
      p. 299                                                 XIII. 24. 26.
    Der Jura, 1858, p. 812                                      B. 44. 48.

  Ritgen.--Nova Acta Leopold., XIII. Part 1, 1826, p. 329, pl. 16.
                                                                23. 4. 68.
  Th. von Sömmerring.--Denkschriften Akad. München,
                       1812, Vol. IV. p. 89, pl. 5-7[2]         23. 3. 28.
                       1820, Vol. VI. pp. 89, 102, pl.          23. 3. 31.

  Spix.--Denkschriften Akad. München, VI. 1820, p. 59           23. 3. 31.

  Theodori.--Notiz für Nat. u. Heilk. 1830, No. 623, p. 101.    24. 2. 28.
    Bericht des naturforschenden Vereins in Bamberg, 1852, p. 17.

  Wagler.--System der Amphibien, 1830, p. 61, figs. 1, 2.

  Wagner (A.).--Abhandl. Bayerischen Akad.,
            II. 1837, p. 163, pl.                               23. 3. 41.
            VI. Part 1, 1851, p. 129, pl. 5, 6;
              Part 3, 1852, p. 690, pl. 19                      23. 3. 45.
            VIII. Part 2, 1858, p. 439, pl. 15-17               23. 3. 61.

[Footnote 1: May be consulted on application to the Librarian.]

[Footnote 2: Good figure.]



_Chief English Writings on Ornithosaurians._

  J. S. Bowekbank.--Quart. Jour. Geol. Soc. 1846, p. 7.        VII. 3. 42.
    Quart Jour. Geol. Soc. 1848, p. 2.                         VII. 3. 44.
    Proc. Zool. Soc. 1851, p. 14.                            XVIII. 18. 3.

  W. Buckland.--Geol. Trans. Ser. 2, Vol. III. p. 217.         XIII. 2. 8.
    Geology and Mineralogy, Vol. I. p. 221, Vol. II. p. 31, pl. 21, 22.
                                                             _Zz_. 34. 10.

  T. H. Huxley.--Quart. Jour. Geol. Soc. 1859, p. 658.         VII. 3. 35.
    Introduction to Classification of Animals, 1869, p. 110     B. 41. 70.
    Proc. Zool. Soc. 1867, p. 417.                          XVIII. 18. 19.

  G. A. Mantell.--Geol. Trans. Ser. 2, Vol. V. p. 170.        XIII. 2. 10.
    Quart. Jour. Geol. Soc. Vol. II. p. 104.                   VII. 3. 42.

  R. Owen.- Geol. Trans. Ser. 2, Vol. VI. 1840, p. 411.       XIII. 2. 12.
    Brit. Assoc. Reports, 1841, p. 156.                         II. 6. 10.
    Quart. Jour. Geol. Soc. Vol. II. p. 96.                    VII. 3. 42.
    British Fossil Mammals and Birds, 1846, p. 545.             IX. 5. 15.
    Odontography, Vol. I. p. 273.                              IX. 10. 23.
    Dixon's Geology of Sussex, 1850, p. 401.                    VII. 1. 5.
    Palæont. Soc. Monograph, Owen, 1851, p. 80.             XVIII. 14. 17.
    Proc. Zool. Soc. 1851, p. 21.                            XVIII. 18. 3.
    British Assoc. Reports, 1858, p. 97, sec.                   II. 6. 27.
    Philosophical Trans. Royal Soc, 1859, Vol. 149, p. 161.     15. 3. 61.
    Palæontographical Soc. Monograph, 1859.                     XVIII. 14.
                                      1860.                  XVIII. 14. 9.
    Palæontology, p. 244.                                       B. 46. 29.
    Anat. Vertebrates, Vol. I. pp. 6, 18, 161, 175, 192, Vol. II.
      p. 13.                                                   IX. 11. 22.

  H. G. Seeley.--British Assoc. Reports, 1864, p. 69, sec.      II. 6. 33.
    Annals of Natural History, 1865, Vol. XV. p. 148.        XIII. 30. 29.
                               1866, Vol. XVII. p. 321.      XIII. 30. 31.
                               1869, Vol. III. p. 465.       XIII. 30. 37.
    Index to Aves Ornithosauria and Reptilia, p. 4, p. 89.     VII. 6. 71.




INDEX.


  Affinities, 24, 94
  Albatross, 31
  Alisphenoid, 81
  Appendix, 129
  Archæopteryx, 8
  Aspect, 105
  Astylica, 97
  Atlas and axis, 64
  Avian carpus, 52


  Basi-occipital bone, 78
  Basi-sphenoid, 80
  Bat, 31, 105
  Birds, 52
  Blainville, 97
  Body, 108
  Bonaparte, 109
  Brain, 25
  Brain-cavity, 87
  Buckland, 60
  Burmeister, 17


  Cambridge upper Greensand, 2
  Camel, 47
  Carp, 79
  Carpus, 48
  Carruthers (Mr), 106
  Caudal vertebræ, 75
  Cerebral lobes, 87
  Cervical vertebræ, 65
  Cetaceans, 30
  Chameleon, 31, 34, 37, 41, 47, 72
  Chelydra, 61
  Chrysochloris, 42, 47
  Ciconia marabou, 86
  Circulation, 100
  Classification, 108
  Claw phalange, 59
  Cod, 79
  Coracoid, 32
  Cranium, 80
  Crocodile, 31, 35, 37, 41, 47, 63, 69, 83, 93, 95, 97
  Cuvier, 7, 92
  Cycnorhamphus, 111


  Delphinidæ, 83
  Dentary bone, 92
  Dicynodonts, 61
  Dimensions, 103
  Dimorphodon, 112, 60
  Dinornis, 67
  Dinosaurs, 99, 61
  Dipnoal reptiles, 99
  Dorsal vertebræ, 69


  Echidna, 61
  ?Eggs, 106
  Epipubic bones (see prepubic bones)
  Evidence that Pterodactyles were Reptiles, 5


  Facial bones, 91
  Families, 110
  Femur, 62
  Fibula, 63, 22
  Food, 105
  Fore-arm, 48


  Gallus domesticus, 90, 82, 34
  Genera, 111
  German Pterodactyles, 106
  Goldfuss, 11, 63
  Goose, 92
  Grouping of reptiles, 97
  Gypogeranus serpentarius, 42


  Habits, 104
  Hand, 53
  Hare, 87
  Head 18, 77, 106
  History, 3
  Horse, 41
  How the meaning of the word reptile is lost, 98
  Humerus, 38
  Huxley (Prof), 86, 116


  Ichthyosaurus, 34, 37
  Iguana, 41, 47, 69, 82
  Ilium, 60
  Ischium, 60


  Jerboa, 64


  Kangaroo, 55, 69


  Ligamentum teres, 62
  Lower jaw, 91
  Llama, 77, 69


  Malar bone, 107
  Mammalian Affinities, 31, 34, 87, 41, 42, 61, 62, 69, 75, 79, 83,
    86, 94, 105
  Manubrium, 29
  Marsupial bones, 61, 110
  Materials, 1
  Mergus merganser, 31
  Metacarpus, 53
  Metatarsus, 63
  Meyer (H. von), 17, 109
  Mole, 30, 37
  Monimostylica, 97
  Monitor, 41, 47, 69, 72, 86
  Monotremata, 34
  Mould of Brain-cavity, 87


  Objections to Prof. Owen's grouping, 99
  Occipital bones, 81
  Oken, 10
  Optic lobes, 84
  Orbito-ethmo-sphenoid bone, 85
  Orbits, 107
  Organization, 7
  Ornithocephalus, 111
  Ornithocheirus, 112
  Ornithorhynchus, 88
  Ornithosauria, 27
  Ossemens fossiles, 7
  Ostrich, 52, 58, 86
  Owen (Prof. R.), 3, 29, 32, 36, 48, 54, 56, 64, 66, 69, 75, 78, 88,
    91, 92, 98, 108, 115


  Pachyrhamphus, 111
  Parrot, 87
  Palæontology, 109
  Parietal bones, 81
  Parker (Mr W. K.), 79
  Pectoral girdle, 28
  Pelvis, 59
  Penguin, 8, 69
  Petrosal, 82
  Phalange, 56
  Plan of organisation, 25
  Pneumatic cavities, 23, 26, 100
  Porpoise, 86
  Post frontal, 107
  Premaxillary bones, 91, 107
  Prepubic bones (prepubic), 61, 110, 111
  Pterodactyle's place in nature, 102
  Pterodactylus, 111
  Pteroid bone, 48
  Pterosauria, 99, 108
  ?Pterygoid end of palatine bone, 91


  Quadrate bone, 89, 107
  Quadrato-jugal, 90
  Quenstedt, 17, 21


  Radius, 42
  Reptilia, 94
  Respiration, 26, 100
  Restoration, 103
  Rhamphorhynchus, 111
  Ribs, 108
  Roc, 5


  Sacrum, 73
  Scapula, 35
  Scink, 41, 72
  Second phalange, 57
  Sömmerring, 10
  Species, 112
  Squamosal bone, 81
  Stannius, 97
  Sternum, 28
  Streptostylica, 97
  Struthious birds, 31, 72


  Tarso-metatarsus, 63
  Teeth, 92
  Tibia, 62


  Ulna, 43


  Vertebral column, 64
  ?Vomer, 88


  Wagler, 11
  Wagner, 14
  Walker (Mr J. F.), 87
  Walking, 105
  Walrus, 79
  Wing-finger, 66

THE END.


Cambridge:[** Old Eng]

PRINTED BY C. J. CLAY, M.A. AT THE UNIVERSITY PRESS.


PLATE I.[AB]

Sternum and Scapula.

  Fig.  1. Fore-part of sternum showing the ovate synovial facet
             for the coracoid. =J=._a_.1, p. 28.

                           ------------------

        2. Outside of the proximal end of a right scapula.
             Largest specimen. =J=._a_.3, no. 2, p. 35.

        3. Outside of greater portion of a left scapula. =J=._a_.3, no. 13.

        4. Inner side of a small right scapula. =J=._a_.3, no. 12.

        5. Outside of proximal end of a right scapula. =J=._a_.3, no. 3.

        6. Surface of =J=._a_.3, no. 3. articulating with humerus.

        7. Outside of distal end of a scapula. =J=._a_.4, no. 1.

        8. View of the distal termination of a scapula.

        9. View of proximal end of left scapula looking from the distal
             toward the articular end. =J=._a_.3, no. 17.

       10. Proximal end of right scapula where united with coracoid,
             looking at the scapula from the articulation.
             =J=._c4_.18.6. Compare fig. 6.

       11. Inner surface of same specimen showing the pneumatic
             foramen at the union of scapula and coracoid.

       12. Outer view of the same specimen.


[Footnote AB: For the Lithographic details of plates 1 to 3, the author
is not answerable. Accidents happened to these plates in the printing,
and they were replaced without his knowledge by good copies; which
however have sometimes deprived the bones of their characters.]

SCAPULA

Pl. 1.

[Illustration]


PLATE II.


Coracoid and Radius.

  Fig.  1. Outer side view of left coracoid. =J=._c3_.16.5, p. 32.

        2. Back view of the same specimen showing the surface
             which unites with the scapula.

        3. Outer side view of perfect right coracoid. =J=._c4_.18. 5.
             Near the figure 3 is the pneumatic notch.

        4. View of the proximal articular surface of a right coracoid.
              =J=._a_.2, no. 23.

        5. Inner view of distal end of left coracoid. =J=._a_.2, no. 18.

        6. The distal articulation of the same specimen.

                           ------------------

        7. Fragment of proximal end of radius 4/5 nat. size. =J=._a_.11,
             no. 7, p. 46.

        8. Proximal end of radius. =J=._a_.11, no. 1.

        9. Proximal articular surface of radius from the same
             specimen.

CORACOID AND RADIUS

Pl. 2.

[Illustration]


PLATE III.


Radius and Ulna.

  Fig.  1. Inner view of distal end of right radius. =J=._a_.10, no. 2,
             p. 44.

        2. Outer view of distal end of right radius. =J=._a_.10, no. 3.

        3. Distal articulation of right radius. =J=._a_.10, no. 6.

                           ------------------

        4. Inner view of proximal end of ulna with olecranon
             anchylosed, p. 45.

        5. Side view of the same specimen. =J=._a_.9, no. 1.

        6. Proximal end of ulna from which the olecranon has come
             away. =J=._a_.9, no. 5.

        7. Proximal articular surface of same specimen.

        8. Proximal articular sur&ce of ulna. =J=._a_.9, no. 4.

        9. Proximal articular end of ulna from which the olecranon
             has come away.

                           ------------------

       10. Distal end of right ulna. =J=._a_.13, no. 5, p. 43.

       11. Distal articulation of the same specimen.

       12. Distal end of left ulna. =J=._a_.12, no. 3.

       13. Distal articulation of the same specimen.

RADIUS AND ULNA

Pl. 3.

[Illustration]


PLATE IV.

Humerus.

  Fig.  1. A nearly perfect right humerus, from Ashwell. =J=._a_.6,
             no. 30, p. 38.

        2. Same specimen seen from the proximal end, so as to display
             the distal end, twisted at right angles with the radial
             crest. The pneumatic foramen is on the anterior and
             radial side.

        3. Proximal end of left humerus showing the radial crest
             perfect. =J=._a_.6. 25.

        4. Articular surface of same specimen showing the termination
             of the radial crest.

        5. Posterior aspect of proximal end of right humerus. The
             pneumatic foramen is on the posterior and ulnar side.

        6. Proximal articular surface of left humerus. =J=._a_.6, no. 2.

        7. Distal end of right humerus. =J=._a_.6, no. 29.

        8. Distal articulation of left humerus. =J=._a_.6, no. 45.

        9. Distal end of same specimen.

       10. Distal end of left humerus. =J=._a_.6.20.

       11. Distal end of right humerus. =J=._a_.6.46.

       12. Distal end of left humerus. =J=._a_.6.34.

       13. Distal end of left humerus from a specimen lent by
             J. B. Lee, Esq.

       14. Distal end of left humerus. =J=._a_.6.35.

HUMERUS

Pl. 4.

[Illustration]


PLATE V.

Carpal Bones.

  Fig.  1. Distal surface of right proximal carpal bone, p. 48.

        2. Same specimen seen from outer end, showing the large
             unarticular surface, above is a part of the distal
             articulation. =J=._b_.1, no. 1. (figured upside down).

        3. Proximal articular surface of right proximal carpal bone.
             =J=._b_.1, no. 7. The right upper part is for the radius,
             the left lower part for the ulna.

        4. View of same specimen (upside down) from the ulnar side.

        5. View of same specimen from the radial side.

                           ------------------

        6. Portion of distal articular surface of a right distal carpal
             bone. =J=._b_.3, no. 23, 4/5 nat. size, p. 50.

        7. Front radial side of right distal carpal. =J=._b_.3.24.

        8. Back ulnar side of the same specimen.

        9. Proximal articular surface of the same distal carpal.

       10. Distal articular surface of the same distal carpal.

       11. View of the proximal articular surface of the same
             distal carpal, seen from the inside.

       12. Perfect element of left distal carpal bone showing the
             distal carpal bone to be composite.

       13. Distal surface of a right distal carpal of another genus.
             =J=._b_.3, no. 20.

                           ------------------

       14. Lateral carpal or pisiform bone, seen from the inside, the
             distal articular talon partly broken. =J=._b_.4, no. 2.

       15. Lateral carpal seen from the outside. =J=._b_.4.9.

       16. Same bone showing the distal articulation, p. 51.

       17. Lateral carpal bone of a different genus, seen from the
             inside.

CARPAL BONES

Pl. 5.

[Illustration]


PLATE VI.

Wing Metacarpal Bone, &c.

  Fig.  1. Fragment of the proximal end of a large wing-metacarpal
             bone. =J=._b_.5, no. 9. It is figured upside down,
             a part of the surface articulating with the distal carpal
             bone being over the fig. 1, p. 53.

        2. Aspect of the proximal articular sur&.ce of the wing-metacarpal
             bone. =J=._b_.5, no. 3.

        3. Exterior aspect of the same specimen.

        4. Inner aspect of another proximal end. =J=._b_.5, no. 4.

        5. The greater part of a small wing-metacarpal bone.
             =J=._b_.5, no. 1. Imperfect at the distal end.

        6. Distal end of a wing-metacarpal bone. =J=._b_.5, no. 31.

        7. Front aspect of the same specimen.

                           ------------------

        8. Distal end of metatarsal bone or of a metacarpal bone
             of a small finger. =J=._b_.8, no. 1.

        9. Lateral aspect of a similar bone. =J=._b_.8, no. 2.

                           ------------------

       10. Outline of the imperfect distal termination of a bone
             regarded as left metatarsus of an Ornithosaurian.
             =J=._b_.13, p. 63.

       11. Front aspect of the same specimen.

                           ------------------

       12. Articular aspect of proximal end of first phalange of the
             wing-finger, from which the terminal epiphysis has
             come away. =J=._b_.6, no. 10.

       13. Diagram outline of the same specimen, p. 56.

WING-METACARPAL BONE, &c.

Pl. 6.

[Illustration]


PLATE VII.

Wing Finger.

  Fig.  1. Exterior aspect of proximal end of first phalange of the
             wing-finger. =J=._c3_.16.12, p. 56.

        2. Inner aspect of proximal end of a small wing-metacarpal
             bone which has lost its proximal epiphysis; it shows
             the notch for the pneumatic foramen. =J=._c1_.8.8.

        3. Fragment of the proximal end of a large wing-metacarpal
             bone, showing near the fig. 3 part of the articular
             surface. =J=._c3_.15. 10.

        4. Distal end of 1 first phalange of the wing-finger.
             =J=._c6_.31. 7, no. 1.

        5. Distal articular surface of a first phalange.

        6. Distal end of a first phalange. =J=._b_.6, no. 4.

                           ------------------

        7. Proximal end of the second phalange of the wing-finger.
             =J=._c2_.12.12, p. 57.

        8. Proximal end of a small second phalange. =J=._b_.7, no. 7.

        9. Proximal end of a large second phalange. =J=._b_.7, no. 4.

                           ------------------

       10. Side view of distal end of right femur. =J=._b_.11, no. 11,
             p. 62.

WING FINGER

Pl. 7.

[Illustration]


PLATE VIII.

Pelvis, Femur, Tibia, &c.


  Fig.  1. Fragment of a large right os innominatum. The faint
            T-shaped lines in the acetabulum indicate the limits
            of the three component pelvic bones; fig. 1 is placed
            at the posterior border of the ischium. =J=._b_.10, no. 1.

        2. Imperfect right os innominatum, with the anterior
            and posterior wings of the ilium broken away.
            =J=._b_.10, no. 4, p. 69.

        3. Imperfect left os innominatum showing the small obturator
            foramen which divides the pubis from the
            ischium. On the anterior border of the pubis is seen a
            depression, which may have given attachment to the
            prepubic bone. =J=._b_.10, no. 3.

        4. Visceral aspect of an imperfect right ischium. =J=._c4_.20.2.

                           ------------------

        5. Exterior side aspect of a right femur. =J=._c2_.11. 20.

        6. Front aspect of the same specimen, p. 62.

        7. Posterior aspect of proximal end of right femur of a
            different genus, showing a pit for the obturator
            muscle. =J=._b_.11, no. 1.

        8. Front aspect of the same specimen.

        9. Outline of the proximal articular end; the obturator pit
            is darkened.

       10. Posterior aspect of distal end of right femur. =J=._b_.11,
            no. 20.

       11. Outline of the distal articular end of the same specimen.

       12. Distal end of a large right femur. =J=._b_.11, no. 12.

                           ------------------

       13. Proximal end of tibia (? front aspect). =J=._b_.12, no. 8.

       14. Another view of the same specimen, p. 62.

       15. Outline of the articular aspect of the same tibia. The
            non-articular part is shaded.

                           ------------------

       16. Claw phalange. =J=._c1_.2.5, p. 69.

       17. Claw phalange. =J=._c_.9, no. 4.

PELVIS, FEMUR, TIBIA, &c.

Pl. 8.

[Illustration]


PLATE IX.

Neck Vertebræ.

  Fig.  1. Anterior aspect of an axis to which the atlas was not
            anchylosed. =J=._c3_.15. 2, p. 64.

        2. Anchylosed atlas and axis seen from the base of the
              vertebra. =J=._c_.1, no. 8.

        3. Anchylosed atlas and axis seen from above. =J=._c_.1,
              no. 14.

        4. Atlas, neural arch imperfect. =J=._c_.1, no. 10.

        5. Anchylosed atlas and axis seen from the side, the neural
             arch of the atlas is wanting. The light space in the
             centrum of the axis is the pneumatic foramen. =J=._c_.1,
             no. 14.

                           ------------------

        6. Large cervical vertebra seen from below. =J=._c_.2, no. 42,
             p. 65.

        7. Small cervical vertebra seen from below. =J=._c_.2, no. 43.

        8. Cervical vertebra seen from behind. =J=._c_.2, no. 5.

        9. Cervical vertebra seen from above. =J=._c_.2, no. 23.

       10. Cervical vertebra seen from the left side. =J=._c6_.27.1,
             no. 4.

       11. Cervical vertebra of another genus seen from the left
             side. =J=._c_.2, no. 13.

       12. Base of the centrum of the last true cervical vertebra.
             =J=._c_.2, no. 40.

       13. Right side of cervical vertebra. =J=._c_.2, no. 7.

NECK VERTEBRÆ

Pl. 9.

[Illustration]


PLATE X.



Back and Tail Vertebræ.

  Fig.  1. Centrum of a vertebra from the region between the neck
             and the back, called pectoral. =J=._c_.3, no. 19, p. 69.

        2. Dorsal vertebra seen from below. =J=._c2_.12.3, no. 2.

        3. The same specimen seen from behind.

        4. Right side view of a dorsal vertebra showing the neural
             spine nearly perfect. =J=._c_.3, no. 20.

        5. The same specimen seen from behind.

        6. Right side of dorsal vertebra showing anterior and posterior
             zygapophyses. The neural spine broken.

        7. Front view of the same specimen. The centrum is seen
             to form but a small part of the anterior articular
             surface.

                           ------------------

        8. Bight side of a sacral vertebra =J=._c_.4, no. 1, p. 73.

        9. Front aspect of the same specimen. The neural arch
             forms part of the intervertebral articulation with the
             centrum.

       10. Side view of the anterior part of a sacrum, presented by
             H. C. Raban Esq. =J=._c_.4, no. 3.

       11. The same specimen seen from below.

       12. Inferior aspect of posterior part of sacrum of a different
             genus. =J=._c_.4, no. 2.

                           ------------------

       13. Large caudal vertebra seen from above. =J=._c_.5, no. 9.

       14. The same specimen seen from beneath, p. 75.

       15. Left side of the same specimen.

       16. Anterior articulation of the same specimen.

       17. Posterior aspect of the same specimen.

BACK & TAIL VERTEBRÆ

Pl. 10.

[Illustration]


PLATE XI.

Cranium.

  Fig.  1. Occipital aspect of the skull of a Pterosaurian. =J=._c_.8,
             no. 2, p. 84.

        2. Anterior aspect of the same skull, showing a transverse
             section of the brain cavity fractured through the
             parietal bones. At its base on each side are seen the
             optic lobes.

        3. Anterior aspect of a Pterodactyle skull of a different
             genus. =J=._c_.8, no. 1. The frontal bones have come
             away from the parietal at the suture, p. 80.

        4. Superior aspect of the same specimen looking upon the
             parietal, supra-occipital, and ex-occipital bones.

        5. Occipital aspect of the same specimen, showing the
             foramen magnum, the absence of the basi-occipital
             bone, and the basi-sphenoid mass.

        6. Side view of the same specimen, showing below the
             girdling occipital crest the excavation for the quadrate
             bone's articulation with the skull, and the forward
             prolongation of the basi-sphenoid mass.

        7. Palatal aspect of the basi-sphenoid bone. =J=._c_.9. To be
             compared with the small triangular mass in fig. 5, p. 85.

        8. Side view of the ethmo-sphenoid mass, =J=._c_.9, showing the
             lateral boundary of the front of the cerebral hemispheres,
             p. 85.

        9. Posterior aspect of the same specimen, showing parts of
             the cups which covered the anterior termination of
             the cerebral lobes.

       10. Anterior view of the cerebral lobes in a natural mould
             of the brain, in the collection of J. F. Walker, Esq.
             It may be compared with figs. 2. and 9, p. 87.

       11. Superior aspect of a natural mould of the brain, showing
             the outline of the cerebral lobes, and the cerebellum
             between them behind. Portions of bone in the temporal
             region are left attached, p. 87.

       12. Side view of the same specimen; one cerebral lobe is
             seen behind the other. The anterior termination of
             this figure may be compared with the posterior outline
             of fig. 8.

       13. Side view of basi-occipital bone, p. 78.

       14. Palatal aspect of quadrate bone, showing the articulation
             for the lower jaw, and the thin quadrato-jugal attached
             to its outside, p. 89.

       15. Exterior aspect of quadrato-jugal and quadrate bones.
             Above the articulation in German specimens is the
             outline of the orbit of the eye.

       16. Anterior aspect of the distal end of a left quadrate bone.

       17. Posterior aspect of the same specimen, showing the
             wing for the pterygoid articulation.

CRANIUM

Pl. 11.

[Illustration]


PLATE XII.

Facial Bones and Lower Jaw.

  Fig.  1. Side view of the dentary bone of Ornithocheirus
             machærorhynchus, showing its posterior attenuation
             towards the palate. =J=._c6_.33.1, p. 113.

        2. Superior aspect of the same specimen, showing the
             palatal groove and tooth sockets.

        3. Articular end of left ramus of mandible, =J=._4_, showing
             its posterior termination, p. 91.

        4. Articular end of left ramus of mandible, =J=._c6_.32. 2,
             fractured through the articulation.

        5. Side view of anterior part of dentary bone of Ornithocheirus
             Cuvieri ? =J=._c_.15, p. 113.

        6. Side view of anterior part of premaxillary bone of
             Ornithocheirus microdon, fractured at both ends.
             =J=._c_.29, p. 116.

        7. Palatal aspect of the same specimen, showing the palatal
             ridge and tooth sockets.

        8. Palatal aspect of anterior part of premaxillary bone of
             Ornithocheirus denticulatus. =J=._c5_.28.1, p. 122.

        9. Side view of the same specimen.

       10. Tooth, showing absorption by the successional tooth,
             on the inner side of the fang. =J=._c_.27, no. 10, p. 92.

       11. Tooth. =J=._c1_.1.4.

       12. Fang of a large tooth. =J=._c_.27, no. 34.

       13. Undetermined [? pterygoid end of palatine bone].
             =J=._c1_.2.7, p. 91.

       14. Other side of same specimen.

       15. 1 Vomer, side view. =J=._c_.10, no. 2, p. 88.

       16. 1 Palatal view of the same specimen.

       17. Pelvis with a bone attached like the middle part of
             =J=._c_.10, no. 2. ?Neural arch of sacral vertebra.

FACIAL BONES AND MANDIBLE

Pl. 12.

[Illustration]

                    *       *       *       *       *


Transcriber Notes


Minor typos were corrected and the Errata list changes were applied.
Standardization of hyphenation was standardized to the most common form
used. Headers for each genera's description was standardized to list the
specimen information first.