_CONTRIBUTIONS FROM THE MUSEUM OF GEOLOGY AND ARCHEOLOGY
                       OF PRINCETON COLLEGE._



                               No. 1.



                       Palæontological Report

                                 OF

                 The Princeton Scientific Expedition

                              OF 1877.


                                 BY

                          HENRY F. OSBORN,
                            WM. B. SCOTT,
                         FRANCIS SPEIR, Jr.


                         September 1, 1878.


                              New York:

         S. W. GREEN, PRINTER, Nos. 16 AND 18 JACOB STREET.

                                1878.


Palæontological Division.

  PROF. JOSEPH KARGÈ,
  ROLLIN H. LYNDE,
  HENRY F. OSBORN,
  JOTHAM POTTER,
  WM. B. SCOTT,
  FRANCIS SPEIR, Jr.


_To the Honorable the President and Board of Trustees of the College
of New Jersey:_

_Gentlemen:_

_I have the honor to transmit herewith the Palæontological Report of
the College Scientific Expedition of 1877._

_The fossils collected by the Palæontological party, and deposited by
the chief of the expedition in the Geological Museum, consisted of
two sets, one numbering some two thousand specimens of fossil plants
and insects from the tertiary beds of Central Colorado, the other of
a considerable series of fossil vertebrates, mostly mammals, from the
tertiary beds of Wyoming Territory, around Fort Bridger. This last
collection has been studied and worked out with unabated zeal and
diligence by the three post-graduate members of the Palæontological
party, Messrs. H. Osborn, W. Scott, and F. Speir, who devoted most of
the time of their course to this special work, with what success this
Report will show._

_It will be a source of gratification to the generous friends of
the College, who furnished means for the Scientific Expedition of
1877, that it not only enriched our Museum to so great an extent,
but did more still by fostering in our College a thorough study of
Palæontology, which could not have been undertaken without such means
as these thus placed at the disposal of our students._

_The fossil insects and plants have been intrusted to the hands of
the best specialists for determination. Dr. S. Scudder, of Cambridge,
Mass., has kindly consented to revise the insects. Prof. G. L.
Lequereux the plants._

                        _Very Respectfully,_

                                          _A. GUYOT,_

  _Director of the E. M. Museum of Geology and Archæology._


                                             Princeton, June 1, 1878.

Sir: We transmit herewith our report upon the Palæontological
collections made by the Princeton party in the summer of 1877.

The following persons constituted the Palæontological division:
Rollin H. Lynde, Henry F. Osborn, Jotham Potter, Wm. B. Scott,
Francis Speir, Jr. The division remained in Colorado from the first
of July until the first of August, when, under the direction of
Professor Kargè, it left the main party, and passed the month of
August in Wyoming, returning in the first part of September. The
Colorado collections were mostly made in the (probable) Miocene
beds near Florissant, and in the beds near the Garden of the Gods,
variously referred to the _Dakota_ and _Wealden_ groups. In Wyoming,
with Fort Bridger as a base of explorations, the division was wholly
occupied in the Bridger series, camping successively on Smith's Fork,
Henry's Fork, and Dry Creek, and exploring the beds adjacent.

It has been our endeavor, in confining our attention to the remains
of vertebrated animals collected during the trip, not merely to
catalogue the direct results, but, by the aid of fresh materials, to
supplement the work of others. For, of the descriptions and data of
the Bridger Eocene Fauna published up to the present time, we find
that even those which have been most accurately prepared are lacking
in important details; and that, owing to imperfect materials, large
gaps yet remain in our knowledge of genera and species named and
classed years ago. Although such supplementary work may appear, at
first sight, tedious and ill-directed, we are confident that in the
end it will prove of some value to science, and that it is therefore
well worthy of our effort. While our field work did not extend beyond
a region previously well explored, we obtained material by means of
which we are able to add a number of new fossils to the Eocene Fauna
of the Bridger group.

In the preparation of this report we have experienced much difficulty
in assigning some of our specimens to their proper genera and
species. For, while we have desired to respect the classifications
made by others, we have in many cases found it impossible to do so,
owing to uncharacteristic definition, which, without doubt, has
been unavoidable. In all cases of uncertainty, we have adopted the
classification which appeared to be the best established. This, in
short, has proved the only available course.

The drawings have been executed with much care as to accuracy of
proportion and outline. They are, with one exception, the work of
a member of the party; and they are inserted simply to illustrate
certain parts of the context, which would be unsatisfactory without
reference to figures of the kind.

Now that the present work is ready for the press, we are very
sensible that it must contain errors which, while they have escaped
our notice, will be readily detected by eyes more experienced. These,
we trust, will be excused, when it is remembered that we are just
entering a field which others have explored for years; and opening a
work which Princeton, with her many other lines of study, has never
hitherto attempted.

We lake this opportunity to return our most hearty thanks to General
Flint, to Judge and Dr. Carter, to Mr. Hamilton, and other officers
and residents at Fort Bridger, who, by their good will and liberal
assistance, contributed largely to our success. Our gratitude is also
due to Professors Leidy and Cope for their generous aid, both in the
way of advice and of material put in our hands for comparison.

The following pages do not embrace descriptions of the entire
collections made by the Princeton party last summer. The valuable
specimens of fossil plants and insects have passed into other hands.

                       Respectfully submitted,

                          HENRY F. OSBORN,
                          WM. B. SCOTT,
                          FRANCIS SPEIR, Jr.

  Dr. Arnold Guyot,
  _Director of the E. M. Museum_.


                          INTRODUCTORY NOTE

                              UPON THE

                    GEOLOGY OF THE BRIDGER BASIN.

Fort Bridger is a government military post, situated on the high
southern plateau of western Wyoming Territory, in the midst of one of
the most interesting geological regions of the world.

The country on all sides was once the bottom of a great eocene lake,
the water of which was probably slightly brackish. Whether this lake
district had direct communication with the ocean, is undetermined as
yet, but there is a possibility that it had.[1]

[Footnote 1: Ichthyic fauna of the Green River shales, Hayden's
Surveys, vol. iii., No. 4, p. 819.]

The tributaries of the Green River, which drain this plateau, render
the valleys along the edges of the streams green and wooded. Beyond
this fertile strip, wide, barren plains extend, covered by a dense
growth of short "sage brush" (Artemisia tridentata).

From the fragmentary debris lying scattered over the surface of the
ground, it would seem as if the various streams formerly were of much
greater size and volume than they now are, and that long after the
eocene lakes had been drained-rivers of considerable size ploughed up
the lake bottoms, excavating an immense area. The formation known as
"Mauvaises Terres" rises abruptly from the valleys, and extends in a
series of plateaus, one above the other, on either side.

The high land shows the effect of violent erosion in two forms;
first, the irregular and jagged cones that appear upon the sides of
the high benches; and, second, the isolated butte structure, rising
directly out of the plain.

The bad lands of Cottonwood Creek, Henry's Fork, Dry Creek, etc., are
examples of the first, and Bridger Butte the best known example of
the second.

Bridger Butte, six miles to the south-west of Fort Bridger, rises to
a height of over a hundred feet, and is about two miles long; its
sides slope steeply up, and its level top serves as a landmark that
can be seen miles away.

The stratification throughout this whole formation is nearly
horizontal, and across the valley can be distinctly noted, owing to
the color and appearance of the various layers.

No satisfactory explanation has been given of the causes which
occasioned the removal of the waters of these lakes, nor of the
agencies necessary to accomplish the great excavations that now
show the former bottoms of the basins. These and like points future
investigation will undoubtedly solve.

It is certain that the level of the lakes varied at different times,
and also that great stretches of marshy land surrounded their borders.

The first fact is proved by the characters of the different layers of
strata; the second by the fossil remains entombed. A careful study
of the formation of the beds of Cottonwood Creek, at a point about
fourteen miles south of Fort Bridger, yielded the following result,
which will serve as an example illustrative of the regular formation
in this section.

Three distinct lines of bluffs are to be noticed, the first rising to
a height of one hundred and fifty feet; from these extends a plain,
gently sloping south-west to the foot of the second line of cliffs;
these seem high, owing to the downward slope of the plain, but they
really rise only fifty feet higher than the first.

On the top of the second, but less broad than the first, extends a
level plain, with a slight dip to the south-east; at the end of this,
the third line rises two hundred feet above the top of the second
line of bluffs, making a total height, in the series, of four hundred
feet above the level of Smith's Fork.

The strata throughout are nearly horizontal, and are of different
color and composition.

Specimens of the rocks and clays from this section were gathered,
and submitted for analysis to Professor Cornwall, of the Scientific
School at Princeton, who has kindly furnished us with the following
notes:

       *       *       *       *       *

No. 1, very friable, light greenish-gray sedimentary rocks,
consisting chiefly of crystalline grains of quartz, orthoclase, and
hornblende (this often in slender crystals), with a little dark
mica, and irregular fragments of a light-greenish, transparent, not
dichroitic mineral. The above are not perceptibly affected by hot
hydrochloric acid. The whole is loosely cemented with a calcareous
clay, containing considerable phosphoric acid. These rocks might
result from the disintegration of a neighboring hornblendic granite.

The greatest mass of the strata is made up of this kind of rock, and
it is this which gives the peculiar color to the "Mauvaises Terres."

Above this in places is found a second kind, which is a light gray
indurated clay, with a slight greenish tint. It contains much fine
crystalline quartz, with considerable carbonate of lime, and a little
phosphoric acid.

It appears to be of similar origin with the first, but was deposited
in quieter waters. This mineralogical evidence is strengthened by the
fact that no remains of mammals were found in strata of this kind,
but only shells regularly deposited in layers one above another.

The third kind is found in thin layers, overtopping the highest line
of buttes; it consists of very fine-grained dark-brown sandstones,
containing a considerable proportion of carbonate and phosphate of
lime. They are hard and tough, and are mechanically deposited, and no
fossils are found in them.

In No. 2 the indurated clay is often found above a coarser sandstone
than No. 1, but of the same general appearance; with the exception
that it contains smooth, rounded pebbles, which were deposited either
on a beach or in running water. In this stratum the fossils found are
separate bones, often showing marks of having been broken before they
were silicified. This would prove that the lake level was changing
continually.

Several skeletons of animals have been found in a standing position,
with their legs slightly stretched out. They were probably mired,
and, being unable to extricate themselves, died in an erect position.
This fact affords evidence that extensive swamps surrounded the
borders of the lake.

The snow-water and the spring rains wear deep gulleys through the
lines of cliffs, and wash down fragments of bones into the dried-up
water-courses. These pieces can generally be traced up to the spot
from which they came, and the rest of the skeleton can so be secured.

The fossils found in the eocene of Wyoming are entirely petrified,
presenting a darker appearance than their matrix; but loose bones
washed out, and subjected to the influence of the sun and rain, often
become bleached so as to resemble in color modern bones.

The state of preservation of the fossils differs according to the
matrix in which they are found. Generally speaking, the remains found
in the lower lines of buttes have been considerably distorted by
pressure; while those from the highest line have suffered very little
from this cause.




MAMMALIA.


PRIMATES.

TOMITHERIUM, Cope.

Ann. Rep. U. S. Geol. Survey of Terrs. 1872, p. 546.

"Dental formula of the inferior series: I. 2, C. 2, Pm. 4, M. 3.
The last molar has an expanded heel. The third premolar consists
of a cone with posterior heel. Fourth premolar exhibits, besides
its principal cone, an interior lateral one and a large heel. The
true molars support two anterior tubercles, of which the inner is
represented by two distinct cusps in one or more of them, and the
external is crescentoid in section. The posterior part of the crown
is wide and concave, and bordered at its posterior angles by an
obsolete tubercle on the inner, and an elevated angle on the outer
side." (Palæontology, Wheeler's Survey, iv (pt. 2), p. 135.)


Tomitherium rostratum, Cope.

Loc. cit., p. 548.

This species exhibits considerable variation, both in size and
proportion of the teeth. We have two specimens of it, one of which
agrees exactly with the measurements given by Professor Cope, while
the other is stouter, and probably belonged to an old male.

The incisors are too much broken for description. The canine has
a long, stout fang, which is subcircular in section; the crown
is compressed, and shows a distinct cutting edge posteriorly.
It is short, and tapers rapidly; in this respect differing from
_Notharctus_, Leidy, which has a long recurved canine. The first
and second premolars are inserted each by a single fang; the third
and fourth by two. The third premolar consists of a simple conical
crown with a small posterior heel; and the fourth has this heel
enlarged, with a small tubercle developed inside and slightly behind
the principal lobe. All the premolars have striated enamel, and very
feebly marked basal ridges.

The true molars are considerably larger than the premolars; the third
is the longest of the series, and the second is the widest. They all
seem to be inserted by two fangs. The posterior fang of the last
molar is a flat quadrate, of the same size throughout, having a great
fore-and-aft diameter, and apparently no nerve cavity. The mandible
is strong but shallow, has a curved alveolus and lower margin, and
the teeth form a curve with convexity outwards. The symphysis is
short and oblique.

This genus presents a close resemblance to the modern _Lemur_,
but at the same time shows several differences. We may give these
differences in systematic order: (1) Greater number of premolars, in
_Tomitherium_ = 4, in _Lemur_ = 2. It will be observed, however, that
the first and second premolars of _Tomitherium_ are very small and
single-rooted, and that their disappearance is a comparatively slight
change. (2) The canines are subcircular in section, not nearly so
much compressed. (3) Greater breadth of the molars in proportion to
their length. (4) Two internal cusps on the molar. (5) Much greater
size of the last molar. (6) Greater depth and thickness of the jaw.
(7) Greater curvature of alveolus and lower margin of ramus. (8)
Longer and more oblique symphysis.

The third and fourth premolars of _Tomitherium_ correspond almost
exactly to the first and second of _Lemur_, but they are not quite so
high and sharp. The interior tubercle of the second premolar is not
so distinct in the latter genus.

In the second specimen the cusps are all low, and the crests
prominent, giving the molars something of the appearance of
_Opisthotomus_. This difference is probably sexual.

_Measurements._

  ---------------------------------+---------+----------+--------
                                   |   M.    |   M.     |  M.
                                   |T. No. 1.|T. No. 2. | Lemur.
  ---------------------------------+---------+----------+--------
  Length of entire molar series    |  ·038   |  ····    | ·032
  Length of premolar series        |  ·017   |  ····    | ·0125
  Length of true molar series      |  ·021   |  ····    | ·0195
  Fore-and-aft diameter of canine  |  ·003   |  ·005    | ·0065
  Length of last molar[2]          |  ·008   |  ····    | ·005
  Width of last molar              |  ·004   |  ····    | ·003
  Length of second molar           |  ·007   |  ·007    | ·0072
  Width of second molar            |  ·005   |  ·006    | ·005
  Length of last premolar          |  ·0055  |  ····    | ·007
  Length of penultimate premolar   |  ·004   |  ····    | ·005
  Depth of jaw at second molar     |  ·012   |  ·012    | ·0095
  Thickness of jaw at second molar |  ·0065  |  ·009    | ·004
  ---------------------------------+---------+----------+--------

[Footnote 2: In measurements of teeth we use the word _length_ to
mean antero-posterior diameter, and _width_ to mean transverse
diameter.]

Specimen No. 1 was found at Cottonwood Creek, and specimen No, 2 at
Henry's Fork, Wyoming.


HYOPSODUS, Leidy.

Pr. Ac. Nat. Sc., 1870, p. 110.

Lower teeth: I. 3, C. 1, Pm. 4, M. 3, in uninterrupted succession.
Last molar has cusps in opposing pairs; the antero-internal cusp on
all the molars is single; the last molar has a heel, and the last
premolar has an inner cusp. The true molar cusps are all high and
simple.


Hyopsodus paulus, Leidy.

Loc. cit., p. 110.

This is one of the most common fossils found in the Bridger Basin.
We have numerous specimens, chiefly from Henry's Fork, exhibiting
a large range of individual and sexual variation. As Dr. Leidy has
already pointed out, the strength and depth of the lower jaw is
extremely variable, increasing with the age of the animal; so that
the most worn teeth are associated with the deepest jaws.

In addition to the jaws and teeth, (which have been very accurately
described), we have a portion of a pelvis and femur, which are
important as tending to confirm the reference of this genus to the
Lemurs.

The _pelvis_ is represented by the acetabulum and a small portion
of ilium and ischium. They resemble the corresponding parts in the
skeleton of _Stenops gracilis_. The acetabulum is a long oval, not
subcircular, deep, and quite narrow from side to side. It appears
to be directed nearly straight outwards. The ilium is narrow, has a
concave gluteal surface, and a prominent acetabular border. The pubis
evidently projected forward, making a right angle with the ilium;
while the ischium is slender and nearly in the same plane with the
ilium. The femur is thoroughly lemurine in shape. The shaft, (as
much of it as is preserved), is straight and sub-cylindrical; it is
not flattened even distally, but becomes very thick and trihedral
in shape just above the trochlea. The trochlea is long, and rises
obliquely upon the shaft; the groove is deep, and the two divisions
are asymmetrical, the external somewhat the larger. The condyles are
large. They are but slightly convex in either direction and project
backwards, and are broadest posteriorly. The internal is the larger.
They are separated by a deep but not wide popliteal groove, which
does not extend into a popliteal fossa. The position and shape of the
condyles are such as show that the femur must have been very oblique
to the tibia, as in the other lemurs. The tuberosities, especially
the internal, are very large and prominent. The whole distal end has
an asymmetrical appearance, owing to the greater size of the internal
condyle.

_Measurements._

                                                           M.
  Breadth of ilium at acetabulum                         ·0065
  Vertical diameter of acetabulum                        ·007
  Transverse diameter of acetabulum                      ·009
  Fore-and-aft diameter of shaft of femur above trochlea ·0065
  Transverse diameter of shaft above trochlea            ·0065
  Width of trochlea                                      ·004
  Length of trochlea                                     ·0075
  Breadth over condyles                                  ·010
  Breadth of inner condyles                              ·005


OLIGOTOMUS, Cope.

Ann. Rep. U. S. Geol. Survey of the Terrs., 1872, p. 607.

"Molars constructed much as in _Hyopsodus_ and _Lophiotherium_, viz.,
with two external subtrihedral cusps which wear into crescents, the
posterior connected by a low oblique ridge with the basis of the
anterior cone of the inner side; the latter with two conic cusps. It
differs from these genera and from _Orotherium_ in the possession of
two premolars; the inferior molars are probably six, leaving four
true molars."


Oligotomus cinctus, Cope.

Loc. cit.

Represented in our collection by the penultimate lower molar, and a
caudal vertebra, which has a remarkably long, slender, and simple
centrum, with rudimentary metapophyses.


OPISTHOTOMUS, Cope.

Wheeler's Survey, Pal. v. iv., pt. 11, p. 152.

"The inferior lower molars do not display a bifid or double anterior
cusp; and the crowns exhibit two anterior cones, and an inner cone
and outer crescent posteriorly. The posterior crescent is well
defined, and is continued on a narrow crest to the anterior inner
tubercle. The posterior molar presents the peculiarity of a series of
three cusps in one line, the median having another or lateral cusp
near it."

This genus has hitherto been found only in the Wahsatch formation;
but we have discovered it to be represented in the Bridger series by
the species _O. astutus_, Cope. Our specimen consists of a part of
the ramus mandibuli containing a single molar tooth.




CARNIVORA


SINOPA, Leidy.

A genus of small carnivorous animals, which Dr. Leidy regards as
intermediate between the recent _Canis_ and the extinct _Hyænodon_.
Owing to the fragmentary condition of the remains found, no
satisfactory generic definition has been given.

From the portion in our collection, we are able to throw some further
light upon the genus, summing up the generic characteristics thus:
Small carnivores, which have the last upper premolar as sectorial
(thus differing from _Hyænodon_), the other premolars simple and
conical.

The sectorial is shorter, antero-posteriorly, than the preceding
tooth; has a short blade of a single lobe, and a large cusp developed
from the posterior part; a cingulum surrounds the entire crown. The
_lower_ sectorial has the blade of a single lobe, and with a short
heel.


Sinopa rapax, Leidy.

Proceedings of Ac. Nat. Sc., 1871, p. 115.

In addition to the molars of the lower jaw, described by Dr. Leidy we
have what corresponds to the third and fourth premolars of the fox,
their dental formulas being probably the same.

The third premolar is small and pointed; differing from the
corresponding tooth in the fox, (1) in its being less compressed, (2)
in its shorter antero-posterior diameter, (3) in the straighter and
more nearly equal margins, and in (4) the absence of a posterior heel.

The tooth is inserted by two fangs, as in _Canis_ and _Hyænodon_. The
posterior shows a rudiment of a third, which is connate with its
entire length above the alveolus. There is an indistinct cingulum
around the entire crown.

The fourth premolar has a very curious shape. The blade of this tooth
resembles the crown of the third, but is smaller. It is inserted by
three fangs, the disposition of which is opposite to that in _Canis_,
the internal, being on the same transverse line as the posterior
external, instead of the anterior, as in _Canis_. From the internal
fang arises a sharp cusp, which is nearly as large as the blade of
the tooth, the two are connate at base. The anterior face of the
crown is much worn, and there is a small anterior heel formed by the
basal ridge. The cingulum is complete all around.

The _maxillary_ does not show the outward bulge at the third
premolar, which is so marked in the fox. The alveolus is straighter,
and the palatine plates are comparatively thicker and flatter. The
infraorbital foramen is oval, and not so much compressed as in the
fox, to which it corresponds very nearly in position, though situated
slightly forward as in _Hyænodon_.

_Measurements._

    _Upper Jaw._                 M.

  Length of third premolar           ·007
  Breadth of third premolar          ·004
  Length of fourth premolar          ·007
  Breadth of fourth premolar         ·007

    _Lower Molars_, from Dr. Leidy.

  Length of last premolar            ·0075
  Length of first molar              ·009

These exhibit nearly the same proportionate size as in the gray fox.

  _Genus_ ----. _Species_ ----.

_Sacrum_ (Plate IX., Fig. 8).--This peculiar sacrum is composed
of only one true vertebra; there may have been one or more
pseudo-sacrals, but this is not certain.

The centrum is very long, strongly depressed, and straight on the
inner margin, not curved as in the sacrum of most mammals. The
anterior articular face is much depressed, and is one third larger
than the posterior. The neural canal is low and subtriangular,
resembling very much that of _Canis_. The pleuropophysial plates for
articulation with the ilia are large and stout. The laminæ are heavy
and concave on their upper side, supporting a very long, stout spine,
which is retroverted and decidedly tuberous at the end.

The pedicles are deeply notched behind; and on the fore part, just
inside the metapophyses, there is a deep fossa.

The chief features of this sacrum are decidedly carnivorous; but to
what genus or family it should be referred we are unable to say.

It has some of the characteristics of _Canis_, but the length
and retroversion of the spine, as well as the size of the
centrum, prevent this classification. In the general form of the
pleuropophysial plates it approximates to the _seals_; while in its
angle and curvature, it partakes of the character of the _Ursidæ_.

The chief point of interest in this fossil centres in the fact that
it was found only a few feet from the brain cast that is described
below.

_Measurements of Sacrum._

                                              M.
  Length of centrum                          ·031
  Long diameter of anterior articular face   ·024
  Long diameter of posterior articular face  ·017
  Width of neural canal                      ·019
  Height of neural canal                     ·011
  Length of neural spine                     ·036
  Extreme width of sacrum                    ·052


MEGENCEPHALON.

Megencephalon primævus. _Gen. et spec. nov._

In close proximity to the pelvis of the _Uintatherium Leidianum_,
in one of the upper beds we found an intracranial cast, separate
from the bone which had enclosed it, and in such preservation as to
warrant a partial determination, at least, of the type to which it
belonged. Wishing to obtain as full information as the nature of the
cast permitted, we put it in the hands of Dr. Spitzka, of New York,
who kindly undertook an examination, and sent us the following as the
result:

  "Sir: The specimen submitted to me is the intracranial cast of
  some species of Placental Mammals. The cranium had been subject
  to the influences of the atmosphere, etc., for a considerable
  period preceding the formation of the cast, and therefore the cast
  reflects the sutural dislocations which occurred in consequence.
  The base of the brain cast it is not advisable to attempt to
  expose, on account of the treacherous nature of the material.
  The convolutions corresponding to the internal aspect of the _Os
  temporale_ have not been clearly demarcated by the bone surface.
  The two narrow eminences on it are casts of the grooves of the
  middle meningeal arteries. The convolutions of the occipital
  surface had been well marked, but somewhat obliterated through
  denudation, etc. The important region bordering on each side of the
  median fissure, and corresponding to the fronto-parietal suture, is
  unfortunately as good as destroyed; and with this destruction the
  key to the interpretation of the specimen is lost. However, this
  much can be stated with absolute certainty, that the frontal region
  is sufficiently well preserved to state that its convolutions do
  not correspond to those of the brain of the tapir, rhinoceros,
  hippopotamus, elephant, pig, horse, hyrax, manatus, or any ruminant
  or cetacean.

  "They also differ in important particulars from those of the
  _Canidæ_, differ less from those of the _Felidæ_, still less
  from the _Ursidæ_, although corresponding to none of them. The
  outline of the cerebral cast is found in two living animals--the
  marine otter and the seal. But in the seal the gyri show the
  transverse interrupting series of sulci, characteristic of extreme
  brachycephaly; and it therefore cannot belong to any animal
  corresponding to the seal.

  "The sea otter's convolutional details are unknown to me, and I
  believe have not yet been studied. I therefore content myself with
  stating that the outline of this cast corresponds to the outline of
  the sea otter's cranium.

  "It would help us a great deal if we could decide the existence or
  non-existence of a bony tentorium. The sutures of this cranium, as
  far as I can reconstruct them, ran as in the diagram.

  "We may state definitely that this was not an ursine, feline, or
  canine brain, nor the brain of any terrestrial viverrine. It is
  an open question between an _aquatic carnivore_ and an _aquatic
  pachyderm_; and although not placing my conclusion on an exact
  basis, yet, in view of the general outline, the course of the
  convolutions, and the course of the sutures, I incline to the
  former view.

  "It certainly corresponds to no known brain of a living creature.
  In one point I was inclined to suspect it to be a pachyderm,
  namely, the decided asymmetry of some of the sulci, but this, by
  itself, is not decisive."

                                      "Dr. Spitzka.

  "308 East 123d street."

The interesting letter quoted in full above, contains as near a
determination of the character of the animal to which the brain
belonged, as the nature of the cast and the materials for comparison
would permit. In a later report, by means of more complete
comparative material, we hope to be able to reach a more satisfactory
conclusion. However, as Dr. Spitzka writes, the _general outline_,
the _course_ of the _convolutions_, and the _line_ of the _sutures_
offer strong presumptive evidence that the cast belongs to one
of the _Aquatic carnivores_. Not far from the brain was found a
sacrum, which is described above as belonging to some carnivore,
though further determination was impossible. Whether there was any
connection between the two is difficult to state. The presence of
an aquatic carnivore in the Bridger eocene is new to science; but,
aside from this, the brain is of a much higher order than previous
discoveries would lead us to expect in such an early formation.

Professor Marsh's researches have led him to form the opinion that
the eocene mammals had brains of a low character; but this specimen
shows that this is not true of all, if it is of most of them. The
convolutions are not only numerous and well marked, but they are
complicated, showing the transverse as well as the longitudinal
folds. To such an extent is this true that the brain will bear
comparison with the very highest modern carnivorous types.

We hope to be able to give further notes upon this interesting
specimen at a later date.




PERISSODACTYLA.


ANCHITHERIUM.

Von Meyer, Jahrbuch für Mineralogie, 1844, p. 298.

Anchitherium ---- ?

A small calcaneum and astragalus of equine type are provisionally
referred to this genus until further material enables us to determine
them with certainty.

The _astragalus_ has narrow and very oblique condyles, which are
more equal in size than in _Orohippus_; the neck is very short,
the internal condyle reaching to the face for the navicular; the
posterior projection of this condyle is much shorter than in that
genus. The articular face for the navicular is quadrate in shape
and concave; the cuboid face is very narrow. The articulation with
the calcaneum is made by a narrow, convex face. When the two are
in position the navicular face of the astragalus is in the same
horizontal line as the cuboid face of the calcaneum, thus resembling
the arrangement of the horse's tarsus rather than that of _Orohippus_.

The calcaneum is a short, slender bone, having the upper and lower
margins convergent toward the tuberosity, and not parallel as in
_Orohippus_. The tuberosity is especially small. The face for the
cuboid is very narrow.

From the articular facets of these two bones we can see that the
tarsus resembled very much that of the modern horse, with a broad,
short navicular, and a narrow cuboid. The strata in which these
remains were found were somewhat higher than those containing the
bones of _Orohippus_.

_Measurements._

                                             M.
  Greatest length of astragalus            0·021
  Greatest breadth of ditto                 ·018
  Length of neck of ditto                   ·005
  Width between the condyles                ·010
  Vertical diameter of face for navicular   ·012
  Transverse diameter of ditto              ·012
  Length of calcaneum                       ·046
  Width of face for cuboid                  ·006

From Henry's Fork.


OROHIPPUS, Marsh.

Am. Jour. Sc. vol iv., p. 207, third series.

_Generic Characteristics._--"The crowns of the upper true molars
are composed of a pair of external cusps similar to those of
anchitherium. There are two corresponding inner tubercles, from
which ridges extend obliquely to the anterior inner margin of the
outer cusps; but the anterior ridge is divided so as to form an
intermediate anterior tubercle. All the teeth preserved have a
distinct basal ridge."

_Species Known._--

  Orohippus pumilus, Marsh.
  Orohippus major, Marsh.
  Orohippus agilis, Marsh.
  Orohippus gracilis, Marsh.


Orohippus pumilus? Marsh.

Specimen obtained. Penultimate and third superior molars, with part
of zygoma.

From Cottonwood Creek.


Orohippus major? Marsh.

_Femur_ (Plate IX., Fig. 1).--The femur has a small, nearly
hemispherical head, developed on a long and slender neck; the head is
but slightly out of the axis of the shaft, and has a large pit for
ligamentous insertion. The shaft is long, simple, and curved slightly
forward. At the proximal end it is broad and flattened axially; below
this it becomes expanded fore-and-aft, but it thickens greatly at
the distal end, just above the condyles. The great trochanter is
large and retroverted, rising above the head, with two prominences
rising from it, one on top, the other back. The digital fossa is
wide and deep, penetrating far into the great trochanter. The second
trochanter is a small rounded ridge; the third trochanter is large
and prominent, curving slightly forward. The condyles are long and
narrow, projecting very far back, and are separated by a wide and
deep popliteal groove. From the external condyle a low ridge runs
obliquely, forming the upper border of the shallow popliteal space.
The trochleæ are long, very convex, deeply grooved, and symmetrical.

_Measurements of Femur._

                                             M.
  Width between head and great trochanter   ·019
  Width at third trochanter                 ·034
  Diameter of head                          ·019
  Width at condyles                         ·028
  Width of trochlea                         ·015
  Height of great trochanter                ·015
  Diameter fore-and-aft of shaft at middle  ·018

The _tibia_ (Plate IX., Fig. 3) is very long and heavy, with broad
proximal articular face, the inner borders of which are prolonged
upward and separated by a groove.

The shaft at the tuberosity is subtriangular, with strongly concave
sides. The tuberosity is prominent, with a deep pit on its upper
surface for the insertion of the ligament of the patella. The shaft
below becomes sub-cylindrical, and decreases regularly in size
downward. Its curvature is forward. The distal articular face is
divided by a smooth ridge into two deep facets. The malleolus is long.

The _fibula_ (Plate IX., Fig. 2) is distinct, straight, and very
slender. The distal end is but slightly expanded, and is strongly
marked by a vertical groove externally. The proximal end articulates
with the overhanging portion of the proximal face of the tibia.

_Measurements of Tibia._

TIBIA.

                                                    M.
  Length                                           ·178
  Width of proximal surfaces (transverse)          ·032
  Width of proximal surfaces (antero-posterior)    ·019
  Transverse diameter of shaft                     ·022
  Antero-posterior diameter of distal articulation ·018
  Transverse diameter of distal articulation       ·018

_The _tarsus_._--The _astragalus_ (Plate IX., Fig. 5) has the
condyles asymmetrical and divided by a deep groove; the head is
narrow, with the neck elongate. The face for the cuboid is small, and
confined to the external border.

The _calcaneum_ (Plate IX., Fig. 4) is long and compressed, with its
upper and lower margins straight and nearly parallel; its tuberosity
is large. The face for the cuboid is small.

The _navicular_ (Plate IX., Fig. 6) is proportionately longer and
narrower than it is in the modern horse. The internal and middle
cuneiforms were probably separate.

_Metatarsals_ (Plate IX., Fig. 7).--Three in number. Are very much
shorter proportionately than in the modern horse. In shape they
are compressed and arched forward. The distal ends are flattened
vertically, arched forward, and deeply grooved in the middle.

The _phalanges_ (Plate IX., Fig. 7) are very short, rather stout, and
very smooth and convex above.

The ungual phalanges are very thin and crescent shaped.

_Measurements._

        ASTRAGALUS.

                                               M.
  Greatest width                              ·029
  Greatest length                             ·022
  Length of navicular facet                   ·017
  Width of navicular facet                    ·012
  Length of tibial trochleæ externally        ·016

          CALCANEUM.

                                               M.
  Total length                                ·058
  Total width                                 ·019
  Depth in front                              ·022
  Length of heel                              ·035
  Depth of heel                               ·018
  Length of cuboid facet                      ·014

          NAVICULAR.

                                               M.
  Width                                       ·009
  Length                                      ·010

        PHALANGES.

                                               M.
  Length of first phalanx                     ·022
  Width of first phalanx                      ·012
  Length of second phalanx                    ·013
  Width of second phalanx                     ·010
  Length of ungual phalanx                    ·005
  Width of ungual phalanx                     ·010


PALÆOSYOPS, Leidy.

  Hayden's Geological Survey of Montana, 1871.--Proceedings
     Academy Natural Sciences, Philadelphia, 1871, p.
     118.--_Limnohyus._--Marsh, American Journal Science and Arts,
     1872, p. 124.

_Generic characters._--The dentition is full, I. 3, C. 1, Pm. 4, M.
3; the same in lower jaw. The internal cones of the superior molars
isolated from the crescentoid crests. One inner tubercle on the
last three premolars. One internal cone on the last superior molar.
In lower jaw, true molars with four acute tubercles alternating in
pairs and connected by oblique crests. The last molar adds a fifth
posterior tubercle. The last premolar lacks the posterior inner
tubercle. The canines are in continuity with the incisors.

A broad, triangular forehead. A wide zygoma. Long, projecting nasals.
Large temporal fossæ. High sagittal crest. Prominent and nearly
vertical occiput.


Palæosyops major, Leidy.

  Survey of Wyoming, 1871, p. 359.--_Limnohyus robustus._--Marsh,
     American Journal Science and Arts, 1872, p. 124.

_Specific characters._--Sagittal crest short and thick. Temporal
fossæ not very deep. Frontals diverge rapidly. Occipital condyles
wide and low; the same is true of the foramen magnum. Meatus
auditorius high and deep. Glenoid cavity shallow; no internal
process. As compared with _P. Paludosus_, post-glenoid process not
so much compressed. Occipital region comparatively higher and not
so concave. The occipital condyles are more prominent. The zygomas
are lighter. Head larger than _Paludosus_, perhaps not so large as
_Vallidens_.

Description from (i) a head, complete, but distorted, with complete
dentition, upper and lower. (2) A head somewhat crushed, and lacking
some portions, with full set of upper molars and canines. (3) A great
number of fragmentary specimens of different parts of the body.

_Dentition._--In the upper jaw the incisors are arranged in a
semi-circle as in _P. paludosus_; they have long fangs and short,
conical crowns, with a decided basal ridge, which is very strong in
the third. They increase from first to third, which is very large and
pointed.

The canines have very large and long fangs (longer than the crowns).
The crowns are very stout and pointed, constituting formidable
weapons. In section they are nearly circular, with a distinct
hinder margin and a slight recurve. A rudimentary anterior margin
is sometimes present, and of the faces thus marked off, the inner
is much smaller and flatter. The general direction is forwards,
downwards, and slightly outwards. There is a diastema of about half
an inch between the incisors and canines.

_Premolars._--The first is very small, about half an inch from the
canine, simple and conical, with an obscurely marked basal ridge, and
two heavy fangs.

Further description of the upper dentition is unnecessary, owing to
the complete work of Dr. Leidy upon the subject.

The _lower incisors_ are placed in a semi-circular row, and are
somewhat procumbent, though hardly as much so as in the tapir. They
are much as in _P. paludosus_, but are relatively smaller, and have
not such distinct basal ridges; features which indicate a departure
from the carnivorous type, and a nearer approach to the herbivorous
type. The lateral incisor, though the largest of the series, is not
so large nor so pointed as in _P. paludosus_. There is no diastema.

The _canines_ are about equal in size to those of the upper jaw,
growing from stout fangs and permanent pulps. The margins of the
crowns are more decided, and are smooth, leaving a very narrow and
flat inner face. A feeble basal ridge. When the jaw was closed, the
lower canines passed inside and in front of the upper.

The _first premolar_ stands immediately behind the canine, is longer
than that of the upper jaw, consisting of a single pointed lobe
implanted by one fang, slightly recurved with a flat inner and convex
outer face. Passing in front of the first upper premolar, it leaves
a considerable diastema between this and the second premolar.

The _mandible_ approximates in form that of the tapir; the lower
border is less curved fore and aft, the alveolar border is slightly
concave antero-posteriorly. The molars converge in front, presenting
a very different arrangement from that in _Sus_. The ramus is heavy,
contracting in depth forward, and very slightly in section. Below the
alveolus, on the interior side, the ramus is greatly swollen for two
thirds of its depth, to accommodate the very long and strong molar
fangs.

The rami converge to the second premolar, where they expand laterally
to the canine alveolus. The symphysis is shorter relatively than
in _P. paludosus_, and the chin is regularly rounded in front. The
mental foramen is below the second premolar. The dental foramen is
small, very high up, and far behind the molars. The alveolar border
ascends rapidly behind the last molar, expanding laterally into two
ridges.

The coronoid is slender and recurved. The condyle is broad, flat
behind, inclines forward internally; there is scarcely any depression
between the condyle and the coronoid. The masseteric fossa is very
wide and deep. The angle of the ramus is broken, but evidently has no
such posterior extension as in _P. paludosus_. It thins out rapidly
behind.

_Measurements._

  --------------------------------------------------+---------+----------
                                                    | P. pal. | P. major.
                                                    +---------+----------
                UPPER JAW.                          |   M.    |   M.
  Length of entire molar series                     |  ·147   |  ·170
  Length of three true molars                       |  ·085   |  ·102
  Length of three premolars                         |  ·058   |  ·068
  Diameter of last molar, transverse                |  ·039   |  ·047
  Diameter of last molar, antero-posterior          |  ·036   |  ·036
  Diameter of second molar, transverse              |  ·036   |  ·040
  Diameter of second molar, antero-posterior        |  ·033   |  ·036
  Length of incisor series                          |  ····   |  ·075
  Fore-and-aft diameter of canine at base           |  ·016   |  ·021
  Length of crown of canine                         |  ····   |  ·033
  Diastema between canines and incisors             |  ····   |  ·013
  Diastema between canines and molars               |  ····   |  ·010
  --------------------------------------------------+---------+----------

  ---------------------------------------------------+---------+----------
                                                     | P. pal. | P. major.
                                                     +---------+----------
                LOWER JAW.                           |   M.    |   M.
  Incisor series                                     |  ····   |  ·073
  Median incisor fang, length                        |  ····   |  ·034
  Median incisor crown, length                       |  ····   |  ·012
  Diameter of median incisor crown, transverse       |  ····   |  ·009
  Diameter of lateral incisor crown, transverse      |  ····   |  ·011
  Diameter of lateral incisor crown, antero-posterior|  ····   |  ·012
  Length of fang of canine                           |  ·055   |  ·052
  Extreme breadth of fang of canine                  |  ·023   |  ·024
  Crown of canine, length                            |  ····   |  ·034
  Crown of canine, fore-and-aft diameter at base     |  ·019   |  ·021
  Diameter of first premolar, antero-posterior       |  ·015   |  ·010
  Diameter of first premolar, transverse             |  ·009   |  ·007
  Diastema between first and second premolars        |  ····   |  ·014
  Length of entire molar series                      |  ·164   |  ·186
  Length of molar series, omitting first premolar    |  ·132   |  ·163
  Diameter of last molar, antero-posterior           |  ·017   |  ·050
  Diameter of last molar, transverse                 |  ····   |  ·027
  Depth of jaw below last molar                      |  ·068   |  ·075
  ---------------------------------------------------+---------+----------

Among other specimens obtained at the divide between Henry's Fork
and Cottonwood Creek, was a nearly complete but somewhat shattered
skeleton of a _Palæosyops major_, found contiguous to the head of
the same, parts of which are just described. Portions of these are
figured on a one fourth scale in Plate II. The description is from a
nearly perfect atlas and axis, several cervical, dorsal, and lumbar
vertebræ, more or less complete, and a portion of the sacrum and
pelvis, in addition to several bones of the limbs.

The _atlas_ has a broad inferior arch, contracted antero-posteriorly,
and deeply notched for the prominent odontoid of the axis. The heavy
superior arch, inclosing a large and depressed neural canal, is
capped by a low tuberosity. It slopes into a flat, and very broad
transverse process, which thickens backwards, and is perforated by
the vertebraterial canal. Forwards the transverse process is notched
for the exit of the first spinal nerve. The anterior or condylar
faces are continuous, deeply concave from above downwards; and
slightly so from side to side; while the posterior faces are oval,
nearly flat, and directed backwards and inwards.

The _axis_ is proportionately small, with a long opisthocœlous
centrum, depressed, and produced forwards into a stout conical
odontoid process, and marked below by a strong hypapophysial keel,
which, developed on the latter half, thickens backwards. The wide
and thin pedicles inclose a high neural canal, support the posterior
zygapophyses and a prominent and peculiar neural spine. The latter
is flattened, broad, and recurved posteriorly, thinning rapidly
forwards into a prow-shaped recurved edge. The transverse processes
arising from the latter half of the centrum are undersized and widely
perforated at base. The anterior faces are very broad, directed
outwards, and slightly rounded from above downwards; they expand as
they diverge (see Fig. 2). The post-zygapophyses are small convex
faces, projecting at the base of the neural spine.

The _remaining cervicals_, five in number, are short, all carinate,
except the seventh, and opisthocœlous; with the faces expanding
only slightly beyond the body of the centrum. A peculiar feature
is a small pit upon the convex anterior face, indicating either
a ligamentous attachment with the antecedent vertebra, or a
remnant of the notochord. This is a feature we have not noticed
elsewhere. A long and heavy transverse process supports a large and
widely-perforated inferior lamella. The pedicles are quite wide at
base, inclosing a large neural canal. The entire upper part of the
arch is unfortunately wanting.

The dorsal centra are smaller than the cervical, slightly
opisthocœlous, and carinate. They are sub-cylindrical anteriorly,
with decided costal surfaces before and behind; approaching the
lumbar region they become subtriangular. A high neural arch
supports a stout, but never very high neural spine; this projects
backwards, keeled in front, expanding and deeply grooved behind. The
zygapophyses are small and nearly vertical. There is a short and
thick transverse process.

The _lumbar_ vertebræ are long, decidedly opisthocœlous, becoming
wider and more depressed as they approach the sacrum. The first
_sacral_ vertebra presents the same characteristics as the last
lumbar, only the body of the centrum is slightly shorter. It has
a very broad pleuropophysial plate. The remaining sacral vertebræ
are broad, and very greatly depressed, rapidly decreasing in size.
The transverse processes are slender. The very low neural spines
anchylose into a long ridge. The number cannot be ascertained, owing
to the fragmentary state of the sacrum. The caudals indicate a tail
of not very great length; as the neural canal is small and persists
in only a few of the anterior vertebræ.

  _Measurements of Vertebræ._                _Pal, major._

                                                          M.
  Atlas, width, including transverse processes          ·195
  Atlas, length of inferior arch                        ·082
  Atlas, height, including superior and inferior arches ·078
  Axis, width, anterior articular faces                 ·110
  Axis, length, excluding odontoid process              ·058
  Axis, height of neural spine                          ·096
  Axis, length of odontoid process                      ·025
  Seventh cervical, length of centrum                   ·037
  Seventh cervical, width of posterior face             ·043
  Dorsals, anterior region, length                      ·038
  Dorsals, anterior region, width, articular face       ·034
  Lumbar, width of posterior face                       ·058
  Lumbar, length of centrum                             ·056
  First sacral, width of anterior face                  ·059

The ribs, of which great quantities of fragments remain, were slender
and not of very great width.

The _femur_, which is figured in Plate I., has a small head,
supported by a short neck. The shaft, very broad below the head,
supports the third trochanter one third of the way down; below which
it takes a cylindrical form, and expands slightly above the trochlea.
The two condyles, separated by a wide and deep popliteal groove, are
nearly subequal in size--the internal somewhat the larger, while
the trochlea is long, narrow, and symmetrical. The great trochanter
rises slightly above the head, and overhangs a long and quite deep
digital fossa. The second trochanter is small. The popliteal space is
slightly concave.

_Tibia._--The proximal end of the tibia is very large, with massive
rugosities for muscular attachment. The two proximal faces are
subequal, slightly convex, and separated by a prominent spine, which
is grooved at the top. The shaft is long, straight, and compressed
antero-posteriorly; the anterior ridge on upper third is very high,
and expands into the tuberosity, which is enormous; while on the
posterior face is a deep fossa just below the head. The distal end of
the shaft is remarkably small, with two concave faces--the internal
the smallest--with a low oblique ridge dividing them. There is a
prominent malleolus.

The fibula (which is a distinct bone) has a small proximal end, and
expands slightly below, with a large external malleolus.

_Measurements of Limbs._

                                                         M.
  Femur, total length                                   .420
  Femur, transverse diameter at distal end              ·098
  Tibia, length                                         ·310
  Tibia, transverse diameter, proximal articular face   ·090
  Tibia, transverse diameter, distal articular face     ·077

The _pelvis_ is described from the right and left ilia, which
are broken as they expand towards the crest; the acetabulum is
fragmentary, but all the parts remain. The ischium and pubis are only
represented by fragments. As figured in Plate V., the acetabulum
is restored from a somewhat smaller specimen. The most striking
feature of the _ilium_ is the long and somewhat constricted neck. The
acetabular border is long and curved forward, thinning gradually as
it approaches the crest; and marked on the iliac surface, near the
acetabulum, by a slight rugosity for the rectus muscle.

The ischial border, while less arched, is probably longer; and the
sacral surface, distinctly defined, indicates that the rounded upper
border of the ilium rarely reached above the sacral spines. There
is a deep groove between the ischial and pubic borders, the latter
disappearing about half way up the iliac surface. The gluteal surface
near the acetabulum is much depressed; above it expands into a broad,
flat, thin plate.

The _ischium_ has a stout neck and thick expansion below; the upper
border is very heavy. From what remains of the _ischium_ and _pubis_
we can infer a large elliptical obturator foramen, a short pubic
symphysis, a narrow and rather slight pubis, with a small nearly
cylindrical neck. The acetabulum is deep, with a thick well-raised
border, and a large, oblong, and very deep pit for the ligamentum
teres.

_Measurements of Pelvis._

                                                         M.
  Ilium, transverse diameter above acetabulum           ·062
  Ilium, long diameter (estimated)                      ·232
  Acetabulum, greatest diameter                         ·050
  Ischium, transverse diameter below acetabulum         ·041
  Pubis, diameter at obturator foramen                  ·035

The _tarsus_ is arranged in the usual Perissodactyle order. The
_calcaneum_ is stout, of good length, tuberous, but not expanding
much at the extremity; presenting two faces for the astragalus, of
which the internal is the largest, and a large distal face for the
cuboid. The _astragalus_ is wide, with less asymmetry in the two
articular facets than is common. It articulates with both the cuboid
and navicular.

_Measurements of Tarsus._

                                                        M.
  Astragalus, total width, tibial facets               ·048
  Astragalus, total length                             ·056
  Astragalus, length, navicular facet                  ·046
  Astragalus, width, navicular facet                   ·035
  Calcaneum, total length                              ·120
  Calcaneum, total breadth                             ·057
  Calcaneum, length of tuber calcis                    ·050

All the above were found at Henry's Fork Divide. In another locality,
in connection with a fine head of _P. major_, was found the lower
half of a _humerus_.

The _shaft_ is cylindrical and twisted, expanding widely at the
distal end. Of the two condyles the external is the largest; and,
to quote from Dr. Leidy, "a deep supra-condylar fossa occupies the
front of the humerus, opposed by a deeper and more capacious anconeal
fossa." The greatest breadth between the supracondyloid eminences is
·091 m.


Palæosyops paludosus, Leidy.

  Cont. to Ext. Vert. Faun, _P. lævidens_ Cope. U. S. Geol. Survey of
     Terrs, 1872, p. 591.

_Specific characters._--Second superior molar has but one outer
tubercle. The cones are low as compared with _P. major_. The cingula
are much less developed. The angle of the lower ramus is much longer.
The zygoma is massive and wide. An internal process on the glenoid
cavity. Temporal fossæ very deep. Crest of occiput nearly in same
vertical line as occipital condyles.

The full details of _P. paludosus_, which follow, may seem somewhat
unnecessary, to one familiar with the comprehensive work of Dr.
Leidy upon the subject. Care has been taken not to retrace any of
his steps; and the descriptions given below are of those parts of
the animal which he did not possess at the time of writing. They
include (1) a cranium perfect posterior to the orbits; (2) a right
_ramus_ mandibuli, with full dentition, except the first premolar;
(3) portions of the fore-limbs, scapula, and pelvis, pes and manus,
and many fragments of other parts.

Among the first discoveries on Cottonwood Creek, in a stratum of
fine green sand, was a head of _P. paludosus_, complete posteriorly,
and broken off just behind the orbit. A rear view of this has been
admirably figured in Plate I.

_General appearance._--The base of the cranium is of great width;
the occiput is high, inclined very slightly backwards, and deeply
concave from side to side. The forehead is triangular and narrow.
The temporal fossa is of immense size and depth, leaving a small
intracranial cavity. The zygomas are heavy, and arching widely
outwards give this part of the head a strong resemblance to the
_Felidæ_.

_Description in detail._--The narrow but prominent _basioccipital_
segment is broadest posteriorly and tapers forwards; divided by a
median ridge, which expands anteriorly into a large tuberosity; a
feature also characteristic of the tapir. About half an inch in
advance of the condyles are the condylar foramina. The _condyles_
are formed of the exoccipitals, which are low and of great lateral
expansion. Their junction with the mastoids is marked by a large
foramen. The _par-occipitals_ are short and styliform. The
_supra-occipital_ region is very large, high, and deeply concave
from side to side, much wider than in the tapir, with a marked
interparietal suture. The _condyles_ are wide, but not very deep,
approaching each other very closely below. The _basisphenoids_ are
long and narrow, tapering forwards. The _alisphenoids_ are mutilated,
but indicate large vertical ridges joining the parietals, and heavy
pterygoid processes, perforated at the base by the alisphenoid canal.
They are again perforated by the foramen ovale three fourths of an
inch behind this. This completes the base of the skull.

The _parietals_ are very large, they form nearly the whole of the
temporal fossil; which, deep and wide, enclosing a small cranial
cavity, contrast strongly with the long and shallow temporal fossæ
of the tapir. The parietal crest is very broad, and grooved at the
top. This high crest and deep adjacent temporal fossæ we at first
mistook as pointing to an exclusively carnivorous type. The forehead
has a triangular appearance, from the divergence of the two side
ridges of the sagittal crest. The _postorbital_ processes are very
large, but do not reach the opposing processes of the _malar_. The
orbit is thus left incomplete posteriorly, while in form it greatly
resembles that of the _Sus_. The _squamosal_ encroaches considerably
upon the temporal; and sends outwards and downwards a great zygomatic
process, which arches outwards from the skull as in the _Felidæ_,
and is more powerful than in any living carnivore (Leidy.) A strong
downward direction is especially characteristic, the whole describing
a sigmoid curve. The _mastoids_ are of great size vertically, and
transversely they are confluent with the par-occipitals. A low, thick
process on the internal side of the glenoid cavity prevents lateral
motion.

The _nasals_ are long, broad, and thick, convex from side to side,
narrowing slightly anteriorly. They are straight, as in _Sus_, which
they resemble more than they do either tapir or rhinoceros. The
anterior borders are rounded, and do not reach as far forward as
the symphysis of the premaxillary. The _malar_ is broad and thick,
probably forming but little of the face, being directed downwards
and backwards to meet the zygoma. The postorbital process is short,
and rather larger than Dr. Leidy has indicated. The _maxillaries_,
smaller proportionately than in _Sus_, form posteriorly the floor of
the orbit; while the infraorbital foramen is situated over the last
premolar. The premaxillaries fail to reach the nasals.

_Comparative Measurements of Head._

  ----------------------------------------+----------+---------+-------
                                          |    P.    |   P.    |
                                          |paludosus.|  major. | Tapir.
  ----------------------------------------+----------+---------+-------
                                          |   M.     |   M.    |   M.
  Height of occiput                       |  ·122    |  ·148   |  ·120
  Breadth of occiput at post tympanic     |          |         |
    processes                             |  ·160    |  ·166   |  ·110
  Breadth of cranium at ends of           |          |         |
    post-glenoid processes                |  ·172    |  ·210   |  ·126
  Transverse diameter of occipital foramen|  ·031    |  ·049   |  ·040
  Vertical diameter of occipital foramen  |  ·027    |  ·033   |  ·027
  Depth of occipital condyles             |  ·033    |  ·039   |  ·029
  Breadth of occipital condyles           |  ·040    |  ·049   |  ·041
  Breadth at occipital condyles together  |  ·082    |  ·100   |  ·082
  Width of basioccipital at anterior      |          |         |
   condyloid foramina                     |  ·038    |  ·039   |  ·028
  Width of basioccipital at junction with |          |         |
   basisphenoid                           |  ·025    |  ·032   |  ·020
  Width of crest dividing the temporal    |          |         |
   fossæ posteriorly                      |  ·011    |  ·020   |  ·011
  Breadth of cranium outside of zygomata  |  ·262    |  ·280   |  ·180
  Depth of zygoma                         |  ·046    |  ····   |  ·036
  ----------------------------------------+----------+---------+-------


_Lower jaw_ of _P. paludosus_ described from another specimen.

The peculiar feature of this jaw is its remarkable extension back of
the molar series (a feature which has not been noticed heretofore),
the distance from the last tooth to the angle being greater than the
length of the entire molar series. From beneath the last molar, the
lower margin curves gently up to the symphysis. The alveolar border
is but slightly curved. Behind the last molar the lower margin forms
a sigmoid curve, much more decided than in _P. major_ (first upwards
and then downwards), and the ramus thins out rapidly to the angle,
where it has a slightly raised border; at the diastema the ramus
curves outwards so as to throw the canines out of the line of the
molars. The symphysis is long.

_Dentition._--The incisors, three in number, from length and shape
indicate a semi-circular arrangement, as in most Perissodactyles.
They increase from first to third. The crown of the first resembles
very much that of the ruminants, but has a straight posterior
basal ridge. Its forward edge is worn so as to expose a small tract
of dentine. The second is larger, but very much like the first in
conformation; while the third has an acute conical crown with a
strong basal ridge.

Of the _premolars_ the first is wanting in this specimen. The second
is bilobed, the anterior lobe much the larger. It has a small
accessory tubercle on its anterior slope. The outer face is rounded,
the inner nearly flat. The posterior lobe is very small and obtuse,
and with the inner face slightly grooved. In third and fourth the
valley between the lobes and the groove on their faces enlarge; while
the anterior lobe becomes relatively smaller.

_Measurements of Lower Jaw._

                                                        M.
  Diastema between canine and first premolar           ·024
  Length of entire molar series                        ·143
  Distance between last molar and extremity of angle   ·147
  Depth of jaw at last molar                           ·070

Among the first discoveries on Cottonwood Creek, in connection with
the lower jaw of _P. paludosus_ just described, were an ulna and
radius, and part of the manus and scapula of the same. These have
been figured, together with other fragments belonging to the same
species, in Plate III., and form an interesting complement to the
nearly complete hind limb of _P. major_ previously described.

The _scapula_ has a shallow oval glenoid cavity, which is concave
longitudinally. Separated from it by a narrow notch is a strongly
recurved coracoid, placed on the inner side of the bone. Above the
coracoid the border is thin, and arches inwards and then forwards;
while the glenoid border is much straighter, rising from a slight
tuberosity. The spine rises gradually from the glenoid, and does not
bear any indication of an acromion.

The _humerus_ is represented by proximal and distal extremities. The
latter presents the same characters on a smaller scale as in _P.
major_. Upon the proximal end there is a deep bicipital groove. The
greater tuberosity has a hooked anterior projection, and runs back
into a ridge behind. (See Fig 7, Plate III.)

The proximal end of the _ulna_ (of median breadth anteriorly) narrows
into a prominent ridge behind. This gives a trihedral character to
the shaft. This is persistent, but is less marked as the fore-and-aft
diameter decreases. The remaining features of note are a high
tuberous olecranon expanding behind; a shallow sigmoid, divided by a
deep fossa into two long divergent articular faces; a trihedral shaft
tapering slightly, but distinct from the radius; a narrow distal
extremity, with a small irregular face for the cuneiform.

The _radius_ has a rather short shaft, curved forwards, expanding
below, and placed immediately in front of the ulna. A strong ridge
runs from the external tuberosity up the posterior face of the shaft,
disappearing two inches from the top. The proximal end, fitting
against the ulna by two small faces, forms the greater part of the
elbow-joint, a strong median ridge dividing the proximal face into
two subequal surfaces with well-raised borders. The distal end of
the shaft is rugose, and more prominent than the proximal. It has an
oblong transverse face, which is slightly concave fore and aft. The
position of the radius, immediately in front of the ulna, and its
manner of articulation, remove any possibility of rotation, a feature
in strong contrast with what we should expect from the character of
the head.

_Measurements of Ulna and Radius._

                                                        M.
  Ulna, length, excluding olecranon                    ·224
  Ulna, length of olecranon                            ·080
  Ulna, transverse diameter, proximal surfaces         ·041
  Ulna, diameter of shaft at median line               ·038
  Ulna, fore-and-aft diameter, distal face             ·025
  Ulna, transverse diameter, distal face               ·017
  Radius, proximal face, transverse                    ·048
  Radius, proximal lace, fore-and-aft                  ·030
  Radius, median diameter, shaft                       ·019
  Radius, median diameter distal face, transverse      ·043
  Radius, median diameter distal face, fore-and-aft    ·016

The _manus_ is described from the third and fourth metatarsals, with
three phalanges. The metatarsals are short, with a wide, stout shaft,
flat in front and slightly arched forwards behind. The proximal ends
unite and form a continuous articular face, concave from side to
side; while upon the exposed sides are smooth facets, indicating the
presence of two additional toes of less size. (See Plate III.) The
convex distal faces are marked behind by a slight groove.

The _phalanges_ are very short and broad, the lower facets marked by
a shallow median groove. The ungual phalanx is wide and short, with a
crescentic outline.

_Measurements._

                                                        M.
  Third metatarsal, total length                       ·090
  Third metatarsal, transverse diameter, proximal face ·017
  Third metatarsal, transverse diameter, distal end    ·019
  Second phalanx, length                               ·024
  Third phalanx                                        ·014
  Total estimated length of manus (6 inches)           ·155


Palæosyops vallidens, Cope.

  Proceedings Am. Phil. Society, 1872, p. 487; Hayden's Survey, 1872,
     p. 572.

_Specific characters._--Founded on details of dental structure.
Superior size. In the upper molars two strong transverse ridges
connect the inner tubercle with the outer crescents, inclosing a pit
between them. In the premolars the outer crescents fuse almost into
a single ridge. These united crescents are relatively narrower. The
inner molars are also narrower, and the posterior tubercle of the
last is an elevated cone.

Fragment of a lower jaw containing the two posterior molars. The
measurements of the teeth are identical with those given by Professor
Cope. The depth of the ramus below the last molar is three and one
third inches, and it is slightly heavier below than in _P. major_.

_Restoration of Palæosyops._--The elevation of _Palæosyops major_,
which is taken as a type, was approximately the same as that of
_Palæotherium magnum_ as restored by Cuvier.

The nearly complete ilium, femur, tibia, and tarsus of _P. major_
in our possession, enable us to make the following estimate of the
elevation of the hind quarters.

                                                        INCHES.

  _Pelvis_, height of ilium above acetabulum                 9
  _Femur_ and _tibia_ by actual measurement, allowing for
    bend at the knee                                        26
  _Tarsus_, from astragalus, and cuboid                      3
  _Metatarsus_ and _phalanges_ (estimated from manus of
    _P. paludosus_)                                          8
                                                            --
                                                            46

It is probable that the fore-shoulders were of the same height. From
the atlas, axis, and from other cervicals, several dorso-lumbar
vertebræ, and part of the sacrum, a rude estimate places the length
of the animal at sixty-seven inches, or nearly six feet, including
the head, and excluding the tail.

In general features it strongly resembled the tapir, with stout
body, slender tail, and very short neck, compensated by a proboscis
of considerable length. In comparing the heads of the ancient and
modern representatives of this class of Perissodactyles, the points
of contrast are the wide stout zygomas, the deep temporal fossæ, the
protruding nasals, and the narrow gaps in the dental series of the
older type.

There are also strong points of resemblance in the structure of the
_Palæosyops_ and _Palæothere_. Some of the cranial homologues have
been detailed by Dr. Leidy. The femur of the Palæothere is shorter,
the tibia longer; they are both much stouter. The tarsus of the
_Palæosyops_ is narrower, while the remainder of the Pes is very
similar. The pelvis, and particularly the ilium and acetabulum of
_Palæosyops_, is more palæotheroid than tapiroid. The similarity of
the fore-shoulder in the two types is also striking. The neck of the
_Palæosyops_ was probably shorter.

In the descending series of _Palæotheres_ terminating in the
diminutive _P. minus_, and characteristic of the upper eocene of
France, we have an interesting counterpart in the large family of
_Palæosyops_, of equal diversity of size and characteristic of our
lower eocene, and it is hoped that future discoveries will render a
complete discussion of this interesting coincidence possible.


LIMNOHYUS, Leidy.

  Proceedings Academy Natural Sciences, Phil., 1872, p. 242;
     _Palæosyops_; Marsh, American Journal Sci. and Arts, 1872, p.
     122; Hayden's Survey, 1872, p. 592, Cope.

_Generic characters._--Resembles _Palæosyops_ in general features.
Distinction founded on the possession of two conic tubercles, of the
inner series, on the last superior molar instead of one.


Limnohyus laticeps, Marsh.

_Palæosyops Laticeps._ Am. Journ. of Sc. v. iv. p. 122.

_Specific characters._--"Cranium is broad. The zygomatic arches much
expanded. The nasals are narrow and elongated, and more like the
corresponding bones in Hyrax than those in the larger pachyderms."

Fragments of the upper molar and premolar series. The species is
determined by measurements given by Dr. Leidy of the second upper
molar.


LEUROCEPHALUS, _Gen. Nov._

Established on a specimen having a nearly complete dentition, and
portions of the cranium.

Dental Formula: (I. 3/3, C. 1/1, Pm. 4/4, M. 3/3,) × 2 = 44.

Upper incisors acute, with strong posterior ridges, lower incisors
compressed and laniariform, canines compressed, with serrated
cutting edges; first upper premolar with rudimentary anterior lobe,
last upper molar with rudimentary postero-internal cusp. Molars
constructed as in _Palæosyops_, but higher, with sharper cones and
more erect external lobes. Internal median valley very much deeper.
Little or no depression at the forehead; zygomatic arch round,
comparatively straight and does not project outwards, and with
obscure postorbital process. Premaxillaries short and straight.
Mandible with nearly straight lower margin, and shallow masseteric
fossa; mental foramen single.


Leurocephalus cultridens, _Sp. Nov._

This species was considerably larger than _Palæosyops major_, with
which it shows affinities, as also with _Titanotherium Proutii_. See
Plate IV.

The _Frontal_ is narrow and flat, or slightly arched. It sends out a
strong curved postorbital process, which projects outwards, but not
so much outwards as in _Palæosyops_. The sagittal crest runs back
from the postorbital in a low rounded ridge, rising but little as
it recedes. The superciliary ridge is distinct, and is pierced by
two small venous foramina. The shape of the entire bone is much as
we find it in the dog, except that it does not arch so much. One of
the most marked differences between this genus and _Palæosyops_ is
here shown. In the latter the forehead rises abruptly from behind
the orbit, while in the former there is only a slight rise for
some distance behind the orbit. As the bone is broken here, it is
impossible to state whether there is any rise at all. Probably not,
however. Below the postorbital process, on the lateral aspect of
the bone, there is a low ridge which separates the orbit from the
temporal fossa. The under surface of the frontal is smooth.

The _Nasal_, of which but a small portion is preserved, is flat on
top, but bends downward at the angle.

The _Maxillary_ is long and stout, over the last and penultimate
molars it broadens to form the floor of the orbit, which is of
unusual size. Between the canine and the malar the maxillary arches
inwards, forming a perceptible concavity, at this point it reaches
its greatest vertical height, as it rises to join the nasal. The
alveolar border is curved in two directions, one with the convexity
outwards, and the other downwards. It exhibits no emargination in the
diastema between the canines and molars. The palatine plate is long,
thick, and narrow; it is flat fore-and-aft, but concave transversely,
owing to the elevation of the alveolus; the suture also is raised
slightly. In thickness it varies; being thickest between the canine
and the second premolar, and beyond this becoming thinner. Its
forward termination seems to be obtuse, running for a short distance
along the premaxillaries. The infraorbital foramen is large, situated
over the fourth premolar, lower down, and nearer to the malar than in
_Palæosyops_.

The _Premaxillary_ is rather short and stout; it is slightly
compressed, and ends in a sharp keel on top. Although not so thick
as in _Palæosyops_, it is much larger vertically. The inner surface
is ridged; it has no palatine process, and no spine, so that the
incisive foramen is large and undivided. There was no symphysis
between the two premaxillaries, they do not show even any articular
faces for each other, so that they may not have been in contact
during life. The animal was adult, but not old. The incisive alveolus
is short and straight, and is but little out of the line of the
molars. There is a very long diastema between the incisors and the
canine, and here the premaxillary is deeply notched to allow the
passage of the lower canine.

The _Malar_ is very different in shape and size from the same bone in
_Palæosyops_. Its facial extent is greater, as it articulates with
the maxillary as far forward as the first molar. It is not so broad
from above downwards, but is considerably thicker; the articulation
with the squamosal is by flat surfaces. The postorbital process is
small and indistinct. The orbit is of great size; its breadth, shown
by the maxillary floor is unusual, but its fore-and-aft diameter is
extreme, being nearly twice as great as in a large _Palæosyops major_.

The _Squamosal_ is a short, slender, and trihedral bone; it is not
at all like the squamosal of _Palæosyops_. It is smaller even than
that of _P. paludosus_; its outer margin is not turned up, making the
upper surface concave; it does not project much outward, and scarcely
at all downwards, as this is rendered unnecessary by the flatness of
the forehead. The chief difference, in the size of this bone, between
this genus and _Palæosyops_ is found in the much greater vertical and
lateral diameter of the latter; in length they are about equal. The
glenoid cavity is large, shallow, and transverse.

As a whole, the zygomatic arch is comparatively slender; it is
rounded, and does not project much laterally from the side of the
head; but its chief peculiarity consists in the fact that it is
nearly horizontal. It is thus altogether different from the arch of
_Palæosyops_.

The _Occipital Condyles_ are different from those of that genus.
They are flatter, shorter from above downwards, and proportionately
much smaller; but are expanded laterally in much the same manner. At
the border of the foramen magnum they are gently rounded instead of
having a sharp angle. These borders are segments of circles, but as
the condyles are broken from the rest of the occiput, we cannot infer
from this the shape of the foramen.

The _Mandible_ is long, stout, but comparatively shallow. It is
of nearly uniform thickness throughout, and does not exhibit the
thickening of the alveolus and thinning, of the lower margin, which
is shown in _Palæosyops_, especially in _P. major_; and the downward
and inward arching of the alveolar border is not marked to the same
extent as in that species. The lower border is nearly straight,
and has but one slight emargination just behind the symphysis. The
ascending portion of the ramus rises near the last molar quite
abruptly, and makes an angle of nearly 90° with the horizontal
portion. The masseteric fossa is shallow and obscure, and the
anterior bounding ridge is almost obsolete. This part of the jaw is
very different from any of the species of _Palæosyops_. The symphysis
is quite long, and extends back as far as the second premolar; the
chin is probably rounded. The dental foramen is situated high up in
the ascending portion of the ramus; the mental foramen is placed
below the second premolar; it is large and single.

_Cranial Measurements._

                                                        M.
  Breadth of frontal at postorbital process            ·045
  Breadth of frontal in front of postorbital           ·030
  Breadth of nasal just in front of orbit              ·032
  Length from angle of nares to end of premaxillary    ·1235
  Length of premaxillary                               ·056
  Length of maxillary                                  ·230
  Breadth of palatine process at canine                ·026
  Breadth of palatine process at second premolar       ·029
  Vertical height of maxillary at angle of nares       ·064
  Breadth of maxillary across floor of orbit           ·058
  Fore-and-aft diameter of orbit                       ·054
  Length of malar along maxillary                      ·094
  Vertical diameter of malar behind maxillary          ·029
  Transverse diameter of malar behind maxillary        ·033
  Fore-and-aft diameter of glenoid cavity (about)      ·029
  Vertical diameter of squamosal at end of malar
    articulation                                       ·032
  Transverse diameter of squamosal at end of malar
    articulation                                       ·0325
  Length of ramus mandibuli from symphysis to
    ascending portion                                  ·177
  Depth of jaw at last molar                           ·068
  Depth of jaw at second premolar                      ·061


DENTITION.

Upper Jaw.--The incisors, three in number, are placed close together
in a nearly straight line, which does not make so great an angle with
the line of molars as in _Palæosyops_. They increase regularly in
size from the first to the third, which is very large. They all have
stout rounded fangs, and sharp pyramidal crowns, with strong basal
ridges separated from the acute blades by deep clefts. Between the
incisors and the canine there is a long diastema.

The _canine_ is of great size; it has a swollen fang, and a long
recurved crown which is much compressed, and has sharp serrated
cutting-edges. The external face is the more convex, the internal has
a well-marked basal ridge, and both are longitudinally striated. The
canine is separated from the premolars by a short diastema.

_Premolars._--The first premolar stands by itself, separated by a
short interval from the second. It is implanted by two fangs, and
has a compressed crown with sharp cutting-edges. It is nearly twice
the size of the corresponding tooth in _Palæosyops_, which is simple
and conical. In the specimen under description there is, besides the
principal lobe of the tooth, a rudimentary anterior lobe which gives
the crown an elongate shape. The basal ridge is shown on the inner
side only. The second premolar has a crown which is oval in section.
The external part consists of two sharp-pointed cusps, separated by
a valley, but confluent at base; while the internal division is a
low ridge (not a pointed cone as in _Palæosyops_) with a tubercle
developed behind it. The basal ridge is marked all around, and sends
up a buttress along the antero-external lobe; as is also the case
in the third and fourth premolars. These are enlarged copies of the
second; but have the internal lobe elevated into a sharp cone, and
showing a much stronger basal ridge and deeper median valley. These
teeth differ in several respects from the premolars of _Palæosyops_.
The crowns are higher and the lobes sharper; the basal ridge is more
distinct, and is not interrupted at the internal cusp; the external
ascending buttress is stronger; and there is no fold between the
external lobes of the fourth.

The molars are constructed in a manner which resembles that of _P.
paludosus_ rather than of _P. major_, but its resemblance to the
form shown in _Titanotherium_ is stronger than to either. They have
broad, square crowns, which increase progressively in size from first
to last. There is a convexity running up the median line of the
external lobes, and the two posterior lobes are connected together
at their bases. The first molar does not exhibit such a decided
increase in size over the last premolar as is seen in _Palæosyops_;
the two external lobes are more erect and sharper than in any form
of that genus. The cingulum is complete even across the internal
cones, and the median valley is very deep, as in _Titanotherium_.
There is a conspicuous fold at the junction of the external lobes,
and a minute tubercle between the two anterior lobes; this tubercle
is present only in the first molar, and not throughout the series,
as in _Palæosyops_. The second molar in general form is like the
first; but is larger, has a deeper median valley, more conspicuous
external folds, and a stronger basal ridge. There is also some change
in the proportions of the crown; the first measuring the same in both
directions, while the second is wider than it is long. The last molar
has but one internal cone; the second is represented by a tubercle;
which however is a true rudimentary lobe and not a development of the
basal ridge. In this tooth, the external fold is very large and the
median valley very deep.

Lower Jaw.--The lower molars and premolars are very much like those
of _Palæosyops_, but are longer, narrower, and higher. The incisors
are not at all like _Palæosyops_, but are compressed and laniariform,
with acute crowns and sharp cutting-edges. The canine is not present
in our specimen; but that it was large, is shown by the long diastema
between the upper canine and incisors.

_Premolars._--The first is small, simple, and implanted by a single
fang close to the canine. The diastema between it and the second
premolar is about one half of that in _P. major_. The second premolar
is the most peculiar tooth in the lower series; as it carries the
development of the anterior lobe at the expense of the posterior
lobe, to a still greater extent than in _Palæosyops_., forming a
crown like the blade of the carnivorous sectorial. The third lobe of
the last molar is no longer a simple cone, but a functional lobe,
with two crests running from it, which bound a median valley.

_Teeth Measurements._

                UPPER JAW.                              M.
  Length of entire dental series                       ·275
  Length of incisor series                             ·375
  Length of diastema between canine and incisors       ·018
  Fore-and-aft diameter of canine                      ·019
  Transverse diameter of canine                        ·015
  Length of diastema between canine and premolars      ·0145
  Length of premolar series                            ·083
  Length of first premolar                             ·016
  Width of first premolar                              ·009
  Length of second premolar                            ·021
  Width of second premolar                             ·017
  Length of third premolar                             ·022
  Width of third premolar                              ·022
  Length of fourth premolar                            ·024
  Width of fourth premolar                             ·027
  Length of true molar series                          ·106
  Length of first molar                                ·031
  Width of first molar                                 ·031
  Length of second molar                               ·037
  Width of second molar                                ·040
  Length of third molar                                ·038
  Width of third molar                                 ·041

                LOWER JAW.                              M.
  Length of entire molar series                        ·202
  Length of premolar series                            ·081
  Length of true molar series                          ·121
  Length of second premolar                            ·024
  Width of second premolar                             ·0125
  Length of third premolar                             ·022
  Width of third premolar                              ·014
  Length of fourth premolar                            ·0235
  Width of fourth premolar                             ·0155
  Length of first molar                                ·030
  Width of first molar                                 ·017
  Length of second molar                               ·038
  Width of second molar                                ·021
  Length of third molar                                ·053
  Width of third molar                                 ·024

Found at Henry's Fork Divide.

This may eventually prove to be a species of _Telmatherium_, (Marsh);
but the description given by him of that genus is so brief and
uncharacteristic that it might apply to any of the allied genera.
Indeed, Dr. Leidy has regarded it as a synonym of _Palæosyops_.


HYRACHYUS, Leidy.

Proc. Ac. Nat. Sc., 1871, p. 229, _et seq_.

A genus of tapiroid mammals, which is thus defined: "_Lower Jaw:_
Third molar with two crests; four premolars, third and fourth with
one transverse and one longitudinal crest. _Upper Jaw:_ Seven molars,
first without interior heel; premolars with two transverse crests."
(Cope.)


_Synopsis of Species._

  I. Long diastema between lower canines and molars.
      A. Lower jaw with six molars                       _H. nanus_.
      B. Lower jaw with seven molars.
          _a a._ Upper molars with complete cingulum.
                 Enamel wrinkled.
          _a._ The last molar with two external lobes on nearly
               the same transverse line            _H. intermedius_.
          _b._ Last molar with the external lobes on the same
               longitudinal line                      _H. modestus_.
          _b b._ Upper molars with cingulum incomplete
                 externally.
          _a._ With anterior conical buttress larger than
               anterior lobe.
             α. Buttress separate, and no fold from
                  anterior lobe                       _H. princeps_.
             β. Buttress united, and quite large fold
                  from anterior lobe                _H. imperialis_.

          _b._ With anterior conical buttress smaller than
               anterior lobe.
             α. Tooth large                            _H. eximius_.
             β. Tooth smaller                         _H. agrarius_.

          _c c._ Cingulum only on outer side of first molar,
                 buttress separated by a ridge from anterior
                 lobe, fold from this lobe very prominent.
                                                    _H. implicatus_.

  II. Short diastema between lower canines and molars.

      A. Descending ridge from antero-external point of lower
           molar extends entirely across the crown of the
           tooth anteriorly                         _H. crassidens_.


Hyrachyus imperialis, _sp. nov._

Established on the second and third molars of each upper jaw, and
three premolars, and one lower molar, portions of the skull and
vertebræ.

This species is, with the exception of _H. princeps_, (Marsh), the
largest species of the genus as yet known. It differs from _H.
princeps_ in the greater proportionate length of the molars, in their
larger size, compared with the bulk of the animal, and in the less
separation of the anterior external conical buttress. The third molar
is the largest; the fold extending from the antero-external lobe
into the valley is very conspicuous. The basal ridge (which is very
strongly marked on the posterior edge), is very feebly indicated on
the exterior. The transverse crests are more oblique in the second
than in the third, but in the latter the valley is deeper and the
crests slightly longer. The anterior conical buttress is of great
size, being larger than the anterior lobe. The premolars have,
as usual, one internal cone; the anterior and posterior external
lobes approach close together, while the accessory fold from the
anterior lobe becomes very prominent, reaching the internal cone and
enclosing a valley between itself and the transverse crest. The basal
ridge does not extend around the inner part of the crown as in _H.
agrarius_.

The only lower molar we have, seems to be a penultimate molar of
the right side. The basal ridge is large anteriorly, very short
posteriorly, but does not appear at all upon the sides, as in _H.
agrarius_.

The remaining bones of the skeleton indicate a rather small animal,
the teeth are therefore proportionately very large.

The occipital condyles are small and sessile; they are much extended
laterally, and the external angles are pointed. In other respects
they resemble the condyles of _Palæosyops_. The zygomatic arch is
slender and does not curve outward strongly. We cannot tell how far
the malar encroaches upon the face. After leaving the maxillary it
becomes much compressed; it has no postorbital process. The maxillary
is of unusual breadth, extends far backwards, and it forms the floor
of the large orbit. The mandible is slender and compressed, with a
large dental canal.

The atlas is small, and has narrow transverse processes, which
are perforated by a large vertebraterial canal. The dorsals have
considerably depressed centra, and the ribs are slender.

_Measurements._

                                                        M.
  Length of last molar                                 ·025
  Breadth of last molar                                ·030
  Length of second molar                               ·024
  Width of second molar                                ·0305
  Length of last (?) premolar                          .018
  Width of last premolar                               ·0245
  Length of second lower molar                         ·025
  Width of second lower molar                          ·018

From Henry's Fork Divide.


Hyrachyus intermedius, _Sp. nov._

Established on the upper true molar series of the right side.

This species is intermediate in size between _H. agrarius_ and
_H. modestus_. As in the latter species; the basal ridge extends
around the entire crown of the tooth, with a small interruption on
the antero-external lobe. It is more pronounced, in front and less
behind than in _H. imperialis_. The anterior conical buttress is
not nearly so well developed as in _H. imperialis_; the valleys
are wide, and the descending fold from the antero-external lobe is
obscure, scarcely marked at all in the first. The transverse crests
are strongly arched forwards, and the anterior is very much the
longer. The peculiar feature of the species is the position of the
postero-externa, lobe, which is pushed to the posterior aspect of the
tooth; this is carried so far in the last molar that the two external
lobes stand on nearly the same transverse line. The antero-external
lobe is much the highest point in the tooth, and its the first molar
is remarkably sharp. The enamel is considerably wrinkled, but not
nearly so much as in _H. modestus_.

_Measurements._

                                                        M.
  Length of first molar                                ·012
  Breadth of first molar                               ·0155
  Length of second molar                               ·015
  Breadth of second molar                              ·017
  Length of third molar                                ·0145
  Breadth of third molar                               ·017

From Cottonwood Creek.


Hyrachyus nanus, Leidy.

Pr. Ac. Nat. Sc., 1872, 20.

Henry's Fork.


Hyrachyus agrarius, Leidy.

Pr. Ac. Nat. Sc., 1871, 229.

Henry's Fork.


Hyrachyus eximius, Leidy.

Pr. Ac. Nat. Sc., 1871, 229.

Cottonwood Creek.


Hyrachyus crassidens, _sp. nov._

Established on the left and a portion of the right ramus mandibuli,
containing the first molar.

The jaw presents some differences from the form common in Hyrachyus.
The alveolus is more curved, especially near the ascending portion
of the ramus; the jaw is narrower, and is especially contracted near
the incisive alveolus. The lower margin of the ramus is but slightly
curved. The ramus itself thickens regularly from before backwards,
and is thickest at the last molar; beyond which it becomes thinner
again. The depth of the jaw is comparatively small, and the teeth
have a forward inclination; the mental foramina are not so large as
in other species of _Hyrachyus_, and are four in number.

The incisors are small, arranged in a semi-circle, and have very
much compressed fangs, with somewhat procumbent crowns; the canines
are small, and form a continuous series with the incisors. There
is a diastema between the canine and first premolar; but one which
is shorter than in known species of the genus, and which does not
indicate the usual curve of the upper border of the ramus.

The molar series, (so far as can be judged from their broken
condition), are much the same as in other species; except, perhaps,
in the greater relative size of the posterior lobes, and in the more
complete closing of the median valley by the junction of the two
lobes externally. The ridge which curves downwards and inwards from
the external point of the anterior lobe is unusually well developed,
and curves across the entire crown. The cingulum is feebly shown; it
appears on the anterior and posterior ends of the tooth (first molar)
and for a very short distance on the outside of the tooth opposite
the median valley; there is no trace of it on the inner side.

_Measurements._

                                                        M.
  Length of entire molar series (about)                ·080
  Length of premolar series                            ·033
  Length of true molar series (about)                  ·047
  Fore-and-aft diameter of fang of canine              ·008
  Distance between canine alveoli                      ·009
  Length of diastema                                   ·115
  Length of the first molar                            ·015
  Breadth of the first molar                           ·010
  Depth of ramus below last molar                      ·0245
  Depth of ramus below last premolar                   ·0215
  Greatest thickness of ramus                          ·017
  Length of symphysis (about)                          ·030

Found at Henry's Fork.


Hyrachyus -------- ?

There are three premolars of the upper jaw which we cannot refer
to any known species; but they are too imperfect to justify the
formation of a new species for their reception.

What appears to be a first premolar is inserted by a single broad
fang; it is too much worn to show the characteristic enamel folding,
and is peculiarly broad and short. The second premolar shows the
usual foldings of _Hyrachyus_; save that a distinct valley enters
the tooth from the posterior edge, running forward to the transverse
crest, and inclosed by the curving backwards of the internal cone.
The crown is nearly square; the basal ridge is scarcely marked at all.

_Measurements._

                                                        M.
  Length of first premolar                             ·011
  Breadth of first premolar                            ·016
  Length of second premolar                            ·012
  Breadth of second premolar                           ·014


HELALETES, Marsh.

Am. Journ. Sc. and Arts, 1872, p. 218.

Additional material enables us to give further characteristics
of this genus, which may be thus defined: Mammals, allied to
_Lophiodon_, having a third lobe to the last lower molar, short
symphysis, and with the teeth of the lower jaw forming a continuous
series. Astragalus has narrow, oblique condyles.

                     ? - ?     1 - 1      4 - 4     3 - 3
  Dental formula: I. -----, C. -----, Pm. -----, M. -----.
                     3 - 3     1 - 1      4 - 4     3 - 3

Synopsis of Species.

  A. Teeth small; a small tubercle on the outer margin,
       between the cusps of last upper molar      _H. boöps_.

  B. Teeth much larger and proportionately broader; no
       tubercle on last upper molar            _H. latidens_.


Helaletes latidens, _sp. nov._

_Lower Jaw._--The ramus is stout, and resembles in general form
that of _Hyrachyus_, but the alveolar border is straighter than
in that genus; the ascending portion forms a right angle with the
horizontal portion, and the masseteric fossa is deep. The symphysis
is comparatively short, and there is complete bony union between
the rami, which do not diverge so much as in _Hyrachyus_. As in
that genus, there are several small mental foramina beneath the
premolar series. The dental series forms a nearly continuous line,
the only diastema being a very short one between the first and
second premolars. The _incisors_ have compressed fangs, and are
arranged in a slight curve. The canine is small and subcircular at
base. The _premolars_ also are small; they somewhat resemble those
of _Hyrachyus_ in shape, but are smaller, and have the posterior
lobe not so well developed. The first is implanted by a single
fang, the others by two. The _molars_ (except the last) consist of
two pyramidal lobes, which form transverse cutting-crests, as in
_Tapirus_ and _Hyrachyus_. The basal ridge is shown on the anterior
and internal sides only. Externally the lobes meet at their bases,
inclosing the valley on that side. The last molar is by far the
longest of the series, and consists of three lobes, of which the
anterior is the largest, and the posterior the smallest. The basal
ridge at the anterior part of the tooth is very strongly marked.

_Upper Jaw._--The molars increase in size from first to last with
considerable regularity. The premolars are small, and, as in
_Hyrachyus_, have one single internal cone, which is joined by
transverse ridges from the two outer cusps; the anterior accessory
tubercle is well developed. The first molar is considerably larger
than the last premolar; it is much worn, and does not show anything
more than that there are two internal cones. The anterior conical
buttress is very largely developed throughout the true molar
series. The second and third molars resemble almost precisely the
corresponding teeth of _Hyrachyus_. Their shape, however, is more
nearly square than is usual in that genus.

_Measurements._

        UPPER JAW.
                                                        M.
  Length of true molar series                          ·036
  Length of last molar                                 ·0135
  Width of last molar                                  ·015
  Length of second molar                               ·012
  Breadth of second molar                              ·015
  Length of first molar                                ·0105
  Breadth of first molar                               ·012
  Length of last premolar                              ·009
  Breadth of last premolar                             ·011
  Length of third premolar                             ·008
  Breadth of third premolar                            ·009

        LOWER JAW.
  Length of true molar series                          ·042
  Length of last molar                                 ·018
  Breadth of last molar                                ·009
  Length of second molar                               ·013
  Breadth of second molar                              ·008
  Length of first molar                                ·012
  Breadth of first molar                               ·008
  Length of third premolar                             ·008
  Breadth of third premolar                            ·005
  Diameter of canine at base                           ·006
  Length of symphysis (about)                          ·027

Found at Henry's Fork.




ARTIODACTYLA.


GENERA INCERTÆ SEDIS.

ITHYGRAMMODON, _gen. nov._

Our fragments of this fossil show an animal about the size of the
llama, and approximating more closely to the _Tylopoda_ than to any
living forms.

The genus is established upon the two premaxillary bones, containing
the incisors, parts of the maxillaries, the canine and the first
premolar; besides fragmentary portions of the palatine plates. As
the peculiar features of these remains render them unique, we are
warranted in establishing the genus _Ithygrammodon_.


_Generic characteristics._

The premaxillaries are long, narrow, and very straight, bent slightly
in on their own axis as in _Camelidæ_, but expanded laterally at the
end of symphysis as in _Pecora_. The upward processes are sharply
defined, with a wide, rounded upper border.

The upper incisors are six in number, and _are placed nearly in a
straight line fore-and-aft_, separated from each other and from the
canine by small and subequal diastemas.

The _incisors_ are nearly equal in size, cylindrical in shape, are
placed vertically in their alveoli, and are slightly recurved.

The spine of the premaxillaries is long and thin, giving very long
anterior palatine foramina, as in _Ruminantia_. The premaxillaries,
in position, are close together, showing a very narrow muzzle.

The maxillaries have two well-developed canines, with long, laterally
compressed fangs, recurved and becoming circular in section at the
crowns. The diastema between the canine and the first premolar is
proportionate to that in _Procamelus_.


Ithygrammodon cameloides, _sp. nov._

_Specific characteristics._

The _premaxillaries_ (See Plate X., Figs. 1-4) are long, with a wide,
strongly upward curving process; from the premaxillary symphysis to
the third incisor, they increase in thickness; then narrow slightly
to the maxillary symphysis. The upper margin of the process is smooth
and narrow, curving very gradually upwards; while the lower margin
runs more abruptly up, giving to it a strongly pointed curvature.

The outer surfaces are smooth and slightly convex; the inner are
marked by a wide deep canal running from just behind the premaxillary
symphysis into the maxilla.

The great size of this groove may perhaps be a generic
characteristic; as it is much larger than in _Protolabis_ (Plate X.,
Fig. 6), the modern camels, or any of the other ungulates, recent or
fossil, that have come under our notice.

The premaxillaries do not co-ossify, as the spines are smooth on
their inner side. Just outside the spines, and in front of the
deep groove, the bones are marked by numerous small pits for the
attachment of the muscles of the upper lip.

The portion of the maxilla in which the first premolar is situated,
shows that the maxillaries swell considerably on their alveolar
border; for the canine then narrow gradually for the first premolar
diastema; then swell for its reception, and become very thin in the
diastema between the first and second premolars.

_The Teeth._--I. 3/?, C. 1/?, Pm. (1+)/?, M. ?/?.

The incisors have quite deep fangs, are cylindrical in shape,
vertical in position, and have no basal ridge.

The crown of the first is worn perfectly smooth, flat across the
top, unlike the wearing exhibited in any modern form that has come
under our notice. The others have their crowns broken, but indicate a
nearly subequal series, with the last slightly the largest.

The canines have long, recurved compressed fangs, with rather short
crowns, which are circular in section. They are much larger than in
_Procamelus_ or _Protolabis_ of Pliocene, or the modern camels. (See
X., Figs. 3, 5, 6, 7.)

The first premolar is the only one of the molar series preserved; its
crown is chipped considerably, but nevertheless shows that it had one
fang and no basal ridge. It resembles the incisors in form, but is
slightly narrower and longer.

The genus _Ithygrammodon_ has been placed for the present under
the _genera incertæ sedis_; but its chief features point to an
unmistakable affinity with the ruminants. It is probable that
_Ithygrammodon_ was the representative and the ancestor, in the
eocene age, of that type of ungulates of which the camel and llama
are the modern forms.

The line of descent of the camels was first indicated in the
Proceedings of the Philadelphia Academy, 1875, p. 262; then in the
Bulletin No. I, 1874, p. 25, of the U.S. Geological Surveys of
the Territories, (Government Report of Explorations of 1873, pp.
498-500); and lastly in U. S. Geographical Surveys of Territories,
vol. iv., pp. 341-44.

In the above writings, Professor Cope traces the development of the
modern camels from the miocene genus _Poëbrotherium_, Leidy, showing
the modifications found in _Procamelus_, Leidy, and _Protolabis_,
Cope, of the succeeding age.

From the last work (Wheeler's Survey, vol. iv., p. 342), we will
quote at length:

"The evolution of the existing types of Camelidæ is a good
illustration of the operation of the laws of acceleration and
retardation. In evidence of this we may follow the growth of the foot
and dentition of the most specialized, and therefore the terminal
genus of the series, the American _Auchenia_ ----. It is well known
since the time of Goodsir, that the embryos of ruminants exhibit
a series of superior incisor teeth which disappear early. It is
probable, but not certain, that in the miocene genus _Poëbrotherium_,
as in various contemporary selenodont artiodactyla, the superior
incisors persisted. I have, however, discovered that these teeth
persisted in the Loup-Fork genus _Protolabis_ during adult life.
I have found that one (the second) of these teeth in _Procamelus
occidentalis_ persisted, without being protruded from the alveolus,
until nearly adult age.

"In genera (_e.g._, the bunodont artiodactyla) where the incisors
are normally developed, they appear at about the same time with the
other teeth, and continue to develop to functional completeness.
This development is retarded in _Protolabis_, since they are not so
matured as to remain fixed throughout life in their alveoli.

"In _Procamelus_, the retardation is still greater, since the first
incisor reaches very small dimensions, and is, with its alveolus,
early removed; while the second incisor only grows large enough,
and for a sufficient time, to occupy a shallow alveolus, without
extending beyond it. In the first incisor the process of retardation
has reached its necessary termination, _i.e._, atrophy or extinction;
while in the existing _Camelidæ_ the second incisor also has
disappeared the same way. In ruminants other than _Camelidæ_, the
third or external incisor has undergone the same process, while in
the _Bovidæ_ the canines also have been retarded in development, down
to atrophy."

Professor Cope continuing the discussion of the teeth of these types,
generalizes: "From these and many analogous cases, the general
law may be deduced that _identical modifications of structure,
constituting evolution of types, have supervenea on distinct lines of
descent?_"

This summary of Professor Cope's conclusions has been necessary to
show clearly in this series the probable place of the eocene genus.

From the shape of the premaxillaries and maxillaries, and the
form and position of the teeth the camelline affinities have been
indicated. Future research must be relied on to throw light upon the
structure of the limbs and the axial skeleton; as it is from these
that the conclusive proof must be deduced that _Ithygrammodon_ is the
ancestor of the camels, and that _Poëbrotherium_ is the second link
in the chain, instead of the progenitor.

_Measurements of Ithygrammodon cameloides with Protolabis._

  --------------------------------------------+----------------+-----------
                                              |Ithygrammodon c.|Protolabis.
                                              +----------------+-----------
  Length of alveolar border of premaxillaries |     ·035       |  ·049
  Greatest height of premaxillaries           |     ·017       |  ·022
  Greatest width of premaxillaries at last    |                |
    incisor                                   |     ·013       |  ·01155
  Thickness of premaxillary process           |     ·010       |  ·017
  Length of diastema between first and second |                |
    incisors                                  |     ·0035      |
  Length of diastema between second and third |                |
    incisors                                  |     ·003       |
  Length of diastema between third incisors   |                |
    and canine                                |     ·004       |
                                              |                |
              _Teeth._                   |                |
                                              |                |
  Fore-and-aft diameter of first incisor      |     ·007       |
  Fore-and-aft diameter of second incisor     |     ·0075      |
  Fore-and-aft diameter of third incisor      |     ·008       |  ·011
  Fore-and-aft diameter of canine             |     ·012       |  ·012
  Fore-and-aft diameter of first premolar     |     ·011       |  ·011
  Transverse diameter of first incisor        |     ·007       |
  Transverse diameter of second incisor       |     ·0073      |
  Transverse diameter of third incisor        |     ·0085      |
  Transverse diameter of canine               |     ·0113      |  ·009
  Transverse diameter of first premolar       |     ·005       |  ·007
  --------------------------------------------+----------------+-----------




AMBLYPODA.


(Cope. Wheeler's Survey, vol. iv., pp. 178 _et ss_.)

"Mammalia, with small cerebral hemispheres which leave the olfactory
lobes and cerebellum exposed. The feet short and plantigrade, with
numerous (in the known genera, five) digits, terminating in flat,
hoof-bearing, ungual phalanges. The seven bones of the carpus
distinct, the unciform articulating with both lunar and cuneiform.
The astragalus flat, without trochlear surface, and attached to the
tibia with very little freedom of movement; its distal extremity
divided into two facets, one for the navicular, and the other more or
less for the cuboid. Molars inserted with enamel, with wide crowns
and transverse crests. A post-glenoid process."

This order falls naturally into two sub-orders:

  "I. A third trochanter on the femur, and a fossa for the
  round ligament: no alisphenoid canal; superior incisors
  present                                         _Pantodonta._

  "II. No third trochanter, nor fossa for the round ligament;
  an alisphenoid canal; no superior incisors.     _Dinocerata._"

This sub-order, Dinocerata, includes at present three distinct
genera, _Uintatherium_, Leidy, _Dinoceras_, Marsh, and
_Loxolophodon_, Cope (also probably _Megacerops_, Leidy). These three
genera, in addition to the characters above given, are marked by the
possession of two or more osseous projections from the upper surface
of the head; and of these the posterior pair, developed from the
parietals, are the largest.

Synopsis of genera of


DINOCERATA.

  A. Cervical vertebra? long; median horn-like processes anterior
       to the orbit; nasal tuberosities do not overhang
       the nasal tips.

    (_a_) Last molar, with or without a tubercle, occupying
            the entrance of the valley between the lobes,
            and but one on posterior basal ridge. Temporal
            fossæ not continued beyond the base of the
            parietal processes. Occipital condyles projecting.
                                                     _Uintatherium._

    (_b_) Last molar never has a tubercle at entrance of
            valley, and has two on posterior basal ridge.
            Temporal fossæ continued very far back; condyles
            sessile.                                    _Dinoceras._

  B. Cervical vertebræ short; median horn-like processes
       directly over the orbit; nasal tuberosities overhang the
       entire tips.                                  _Loxolophodon._

Synopsis of species of


UINTATHERIUM.

  A. With a tubercle occupying the entrance of the valley
       between the lobes of the last upper molar.     _U. robustum._

  B. No tubercle at the entrance of the valley.

    (_a_) Nasals divided by a deep groove; slender zygomatic
            arch; dorsal vertebræ compressed.        _U. Leidianum._

    (_b_) No nasal groove; stout zygomatic arch; dorsal
            vertebræ sub-cylindrical                  _U. princeps._


UINTATHERIUM.

  Leidy, Proc. Ac. Nat. Sc., 1872, p. 169.--Cont. to Ext. Vert. Faun.
     of Western Territories, p. 93.--Cope, Hayden's Survey, 1872, p.
     580, etc.

Skull broader proportionally than in the other genera of the order,
ridged and possessing several concavities on the upper surface;
zygomas slender and but little curved; temporal fossæ comparatively
short and have well-defined superciliary margins. The cervical
vertebræ are rather long; the sacrum has four vertebræ; and the tail
is quite long, very flat and broad. The tibia has its proximal face
divided by a prominent ridge into two parts. The dental formula
for the upper jaw is: I. 0, C. 1, M. 6. The molars are small, and
increase from first to sixth. The last is much the largest; in it the
anterior lobe considerably exceeds the posterior in size, and there
may or may not be a tubercle at the entrance of the valley between
the lobes; but there is always one developed from the cingulum at the
posterior part of the tooth.


Uintatherium leidianum, _sp. nov._[3]

[Footnote 3: This species is respectfully dedicated to Dr. Joseph
Leidy, of Philadelphia. The specimens upon which it is established
were found on Dry Creek plateau.]

Established upon a head and nearly perfect skeleton of one
individual, and parts of two more.

In this species, as in most others of the sub-order, the nasals are
of immense length and thickness; they overhang the anterior nares,
and project considerably beyond the premaxillaries; they form more
than half of the entire length of the skull, articulating with the
frontals somewhat behind the orbits; the median suture is distinct
throughout. Instead of having an expanding shovel-shaped forward
projection, as in _Loxolophodon_, they narrow from the median osseous
projections (horn cores?) anteriorly. Above the muzzle they are
strongly curved from side to side, on their upper surface forming
a continuous arch; on the under surface of each bone is a deep
concavity, separated from its fellow by the sutural ridge, which
disappears forwards, near the extremity. On the upper surface of each
nasal, near the forward end, is a large osseous tuberosity which is
directed forwards and outwards; these processes are much smaller than
the corresponding ones in the _Loxolophodon_, while they are larger,
of different shape and direction from those in _Dinoceras_. In this
species they are divided throughout by a deep median groove, which
anteriorly becomes a fissure, and separates the extremities of the
nasals completely. In front of these tuberosities, the nasals taper
very rapidly, and end in sharp points which project downwards and
forwards; this portion of the bones is shorter, sharper, and projects
more decidedly downwards than in _Dinoceras_. Above and slightly
behind the sockets of the cranium, the nasals and maxillaries give
rise to the median pair of osseous projections. These are very
large, subtrihedral at the base, and project upwards, outwards, and
strongly forwards. They differ from the corresponding processes
in _Dinoceras_, in their forward projection, in being longer and
more everted, and in their approach to each other at the base. They
taper quite regularly from base to tip, but do not come to a point;
a section here would be subcircular. They are not so long and are
not knobbed at the ends as in _Loxolophodon_. Their inner curve is
convex, the outer concave; converging below at an angle of 90°, they
are united by a strong ridge, which is raised decidedly above the
surface of the nasals. At their posterior insertion they touch the
frontals, lachrymals, and malars. It is probable that the nasals
send up processes on the internal and posterior side of these median
projections; the sutures between these and the maxillary portions are
marked by slight ridges.

_Frontals._--In our specimen it is very difficult to determine the
exact relations of these bones. The nasals narrow at their posterior
end, and articulate with the frontals by a V-shaped suture which
thus encloses them on each side. It is probable that the frontals
run to some point between the posterior or parietal projections. If
we have discovered the suture, they overlap the parietals, sending
up V-shaped processes, which join the sides of the posterior cranial
projections, and form a deep concavity with them. They constitute a
large part of the interior wall of the orbit, but have no postorbital
processes; the superciliary ridge is very strong, and gradually rises
into a large rounded crest, which joins the posterior projection.
The frontal eminences are large, and situated immediately over the
lachrymals. The upper surface of the frontals is marked by two high
ridges, which probably represent the divided parts of the sagittal
crest; they rise from the anterior margin of the bones, and are
strongest above the frontal eminences. They converge, and then
diverging, together forming an X-like curve (without crossing,
however), gradually disappear posteriorly. These various ridges form
four deep concavities on the upper surface of the skull: (1) The
largest already mentioned, between the parietals and the posterior
part of the frontals; (2) that marked by the suture between the
nasals and frontal, not so large; (3 and 4) two much smaller lateral
ridges between the sagittal and superciliary ridges. This great
irregularity of the upper surface of the head is, so far as is yet
known, peculiar to _Uintatherium_.

_Parietals._--The peculiar feature of these bones is the huge pair
of projections (the so-called "posterior horn cores") to which they
give rise. The outer margin of these processes is nearly straight;
the inner margin for its upper two thirds is also straight, the lower
third curving in a high strong ridge to meet its fellow. The anterior
face is rounded and produced into the long crest of the frontals,
while the posterior face is flattened and produced into a similar
but shorter and higher crest which joins the supra-occipital. At the
base of these processes their greatest diameter is fore-and-aft,
while at the top it is transverse. They project upwards and outwards,
but are not curved as in _Dinoceras_, nor are their upper borders so
much arched. Their greatest diameter at top is at right angles to
the corresponding measurement in this last-named genus. Behind the
ridge which connects these projections, the parietals curve sharply
upward to a high occipital crest; between which and the projections
they form a deep basin whose floor is raised above that formed by
the frontals immediately anterior to it. This arrangement differs
from that of both _Loxolophodon_ and _Dinoceras_, especially from
the latter. The temporal fossæ are of great length, deeply concave,
but rather low from above downwards, formed almost entirely by the
parietals, and bounded posteriorly by a sharp outward curve of these
bones. They are of about the same proportionate length, but higher
and very much deeper than in _Loxolophodon_; and are not nearly
so long as in _Dinoceras_, in which genus the parietals expand
far behind the horn-like processes. In our specimen the posterior
part of the fossa is pierced by numerous small venous foramina,
and corresponds precisely in every way, save that of size, to the
specimen figured by Dr. Leidy. (Cont. to Extinct Vert. Fauna, Plate
XXVI., Fig. 1.)

_The Squamosals_ are large and heavy but encroach little upon the
temporal fossæ; they are situated directly below the large parietal
projections. The glenoid cavity is transverse and straight in this
direction, broad and shallow, with no internal process; and the
post-glenoid process is long and massive. The zygomatic process is
short, stout, high, and trihedral, with a strongly arched upper
margin. The articulation with the malar is by a straight, flat face,
and anchylosis of the two never takes place. The anterior termination
is pointed, and the outer margin is rounded.

_The Malars_ form none of the face. They are long, slender, curved
downwards and backwards, and but little outwards. They are longer,
straighter, and less curved outwards than in either _Loxolophodon_ or
_Dinoceras_; they do not present the sharp angle in the lower margin
shown in the latter genus, nor are they so extensively overlapped
by the zygomatic processes of the squamosal. Posterior to the molar
series, the malars are greatly compressed and very slender, but at
the junction with the maxillaries they become much wider and thicker.
There is no trace of a postorbital process; and the projections from
the under surface of the bone at their junction with the squamosals,
so prominent in Dinoceras, are here rudimentary or absent. As a
whole, the zygomatic arch is very long, slender, simple, curved
upwards and very slightly outwards, so slightly that it is completely
overhung by the superciliary ridge and frontal crest.

_The Lachrymals_ are unusually large, and form the anterior part of
the orbit; they encroach considerably upon the face, and articulate
with the superciliary ridges above. The lachrymal foramen is very
large.

_The Maxillaries_ are of great length, being nearly as long as the
nasals. They extend somewhat beyond the last molar; but the suture
between them and the pterygoids is very obscure. There is a very long
diastema between the canine and molar series, and the lower margin
is arched upwards; above this, between the orbit and the socket of
the canine, there is a large, deep fossa, but we can discover no
infraorbital foramina. The sockets of the canines are very large
and prominent, they curve upwards and backwards to the base of the
median cranial projections, but these are not excavated to receive
them, as is the case in _Dinoceras_. The most peculiar feature of the
maxillary bones is the pair of large horn-like projections, to which,
in conjunction with the nasals, they give rise. These have already
been described, and it only remains to add that they correspond in
position to those of _Dinoceras_, and are therefore much further
forward than those of _Loxolophodon_.

The palatine plates of the maxillaries are long and very narrow; they
are concave transversely, and are separated from each other by a high
median ridge. The posterior palatine foramina are small.

The _Palatines_ are very short, narrow, and concave, and are
separated by a ridge. They are considerably excavated on the
posterior border, in this respect differing from _Loxolophodon_.

The _Pterygoids_ and the pterygoid plates of the alisphenoid are
compressed; the former join the alveolar borders of the maxillary,
which are produced somewhat beyond the last molars. The alisphenoid
canal is very large, but rather short.

The _Premaxillaries_ are of very peculiar shape, somewhat like
a _u_, with one side--the lower--the longer. The upper portion
articulates with the nasals, running along the narial opening to
about three inches from the angle; the free portion is short,
slender, and tapering; it is curved downwards and slightly inwards;
the premaxillaries do not meet, leaving the incisive foramen
unenclosed, and are edentulous. At the end of the upper portion there
are prominent processes for the attachment of the muscles of the
proboscis, which probably resembled that of the tapir.

The anterior narial opening is very large, but is considerably
concealed by the overhanging of the nasals. There is no osseous
septum between the nostrils. The posterior nares are much smaller,
being especially contracted in width; it is divided above by the
_Vomer_, which is very short, and does not reach the palatines. The
nasal cavity thus formed is long, straight, and gradually narrows
backwards.

Of the Mandible we have but a small portion of the right
ramus, comprising the part opposed to the upper canine, from
the dental canal downwards. The jaw at this place has a large
downward-projecting process, very similar to that figured by Marsh
in his plate of _Dinoceras laticeps_. This process curves slightly
outward, and has its external side convex in both directions, and
its internal side convex fore-and-aft, concave from above downwards.
The posterior mental foramen, which is the only one preserved in our
specimen, corresponds in size and position with _Dinoceras laticeps_.
The only difference between the two is a very slight one: in _D._
the curve of the posterior margin of the process is convex; in
_Uintatherium_ it is concave; the angle which the process makes with
the jaw is also greater.

_Cranial Measurements._

                                                           M.
  Length of bony palate                                   ·227
  Length of head along the top                            ·743
  Length of nasals                                        ·398
  Breadth at nasal tuberosities                           ·123
  Distance between median projections                     ·385
  Breadth of head posterior to median projections         ·189
  Breadth of head before posterior projections            ·228
  Breadth of head behind posterior projections            ·312
  Distance between extremities of posterior projections   ·462
  Length of nasals to ridge between median projections    ·234
  Length from ridge between median to ridge between
    posterior projections                                 ·374
  Length of zygomatic arch (straight)                     ·285
  Length from angle of nares to end of nasals             ·162
  Length from angle of nares to end of premaxillaries     ·114
  Width between tips of premaxillaries                    ·053
  Circumference of median projection at top               ·203
  Circumference of posterior projection at top            ·329
  Height of median projections from ridge between them    ·174
  Height of posterior projections from ridge between them ·239
  Length of nasals anterior to nasal tuberosities         ·0415

_Teeth._--These are peculiar for their small size compared with the
bulk of the animal; for their slender fangs, and for the distance
through which these are exposed.

_Upper Jaw._--Formula: I. 0/0, C. 1/1, Pm. 3/3, M. 3/3.

_Canines._--The sockets of these teeth have been already described:
the fangs are very long, somewhat longer than the crown, and the
teeth apparently grew from permanent pulps. The crown is long,
compressed and recurved; the posterior margin is sharp, and exhibits
some indications of a slight serration.

_Premolars._--The first premolar is not preserved in our specimen.
The second and third are subequal, and of about the same
conformation. They are implanted by three fangs, one internal and
two external. The crown is subcircular at the base. The basal
ridge is large, and completely surrounds the crown; above this the
crown becomes somewhat trihedral: and is composed of two pyramidal
lobes, which meet internally and externally, and are divided by a
valley. The summits of the lobes form transverse grinding ridges;
the anterior one is the lower, and is crescent-shaped, while the
posterior is straight; the anterior ridges throughout the series are
much the most worn. The basal ridge is not indented on the outer side
at the opening of the valley as in _Dinoceras_.

_Molars._--The true molars increase in size regularly backwards. The
first molar is larger than the last premolar; it is worn down nearly
to the basal ridge, but shows a small internal accessory tubercle on
the back part of the posterior lobe. The extremities of the lobes
rise into points, and their summits are transversely concave. The
number and arrangement of the fangs in the first and second molars
is the same as that of the premolars; in the last molar there are
but two, which are long and wide, and extend the whole breadth of
the crown. This tooth is by far the largest of the molar series; it
is ovoidal in shape, with the apex at the outer point of the forward
lobe; it is proportionally broader than in _Uintatherium robustum_.
The basal ridge is strong, and extends around the entire tooth, with
some irregularities of outline at the sides. This tooth, like the
others, consists of two pyramidal lobes separated by a valley, which
in this case is wide and deep. The summit of the anterior lobe is the
longer, and extends obliquely across the crown, while the posterior
is nearly straight. The free ends and junction of the lobes are
prolonged into points, which give a tripodal character to the crown.
The outer point of the anterior lobe is the longest of the three, but
the difference is not nearly so marked as in _U. robustum_; the other
two are of about the same height; but the external is spinous in
character, while the internal is stout and obtuse. The anterior slope
of each lobe is steep, while the posterior is long and gentle. As in
_U. robustum_, there is a small rounded tubercle on the inner side
of the posterior basal ridge; but there is no tubercle occupying the
entrance of the triangular valley between the lobes. The enamel of
all the molars is smooth.

_Teeth Measurements._

                                                          M.
  Length of molar series                                 ·148
  Length of premolar series                              ·062
  Length of true molar series                            ·089
  Fore-and-aft diameter of second premolar               ·022
  Transverse diameter of second premolar                 ·023
  Fore-and-aft diameter of third premolar                ·022
  Transverse diameter of third premolar                  ·023
  Fore-and-aft diameter of first molar                   ·023
  Transverse diameter of first molar                     ·026
  Fore-and-aft diameter of second molar                  ·028
  Transverse diameter of second molar                    ·031
  Fore-and-aft diameter of third molar                   ·039
  Transverse diameter of third molar                     ·044
  Distance between last molars                           ·058
  Distance between first premolars                       ·049
  Distance between first molars                          ·074
  Fore-and-aft diameter of root of canine                ·060
  Transverse diameter of root of canine                  ·039
  Length of diastema                                     ·072
  Distance between canine alveoli                        ·080

_Lower Jaw._--Dr. Leidy has very kindly sent us some of the lower
molars of an undescribed _Uintatherium_, which may belong to this
species. They consist of the anterior lobe of the last molar, and
second and third premolars entire. They all have nearly the same
conformation, consisting of three acute pyramidal lobes, of which
the anterior is very much the highest and broadest; the median
lobe is partly separated from the anterior by a valley which opens
outwards, while the valley between the posterior and median lobes
passes completely across the tooth. The highest point of the crown
is the inner end of the anterior lobe; but the difference between
this and the outer end, very great in the molars, becomes slight in
the premolars. The inner end has an accessory tubercle just at the
lip of the anterior lobe, and there is another on the anterior basal
ridge. This latter feature would seem to distinguish it from _U.
robustum_.

The basal ridge is distinct in front and behind, indistinct on the
external side, and entirely absent from the internal.

_Measurements._

        (TEETH, LOWER JAW.)
                                                          M.
  Transverse diameter of last molar                      ·026
  Height of highest point above cingulum of last molar   ·023
  Fore-and-aft diameter of second molar                  ·0285
  Transverse diameter of second molar                    ·023
  Height of second molar                                 ·0215
  Length of fourth premolar                              ·021
  Width of fourth premolar                               ·015
  Height of fourth premolar                              ·020
  Length of third premolar                               ·020
  Width of third premolar                                ·015
  Height of third premolar                               ·014

_Vertebræ._

_Cervical region_ (Plate VI., Fig. 1).--(Only one preserved, probably
fifth or sixth.)

The centrum is short, compared with the dorsals, but is much longer
than the cervical centra of the _Proboscidea_; it is broad and
depressed, oval in form, and slightly opisthocœlous. The zygapophyses
are developed upon tuberous projections of the pedicles; they are
large, flat, and in the same plane with each other. The diapophyses
are very slender and short, and but slightly heavier than the
parapophyses, with which they unite, enclosing a large vertebraterial
canal. At the anterior margin of the parapophysis, a small pointed
process projects downward.

The pedicles are low and very heavy, bounding a narrow neural canal.

The epiphyses are not so completely ossified as they are in the
dorsal region.

_Dorso-lumbar region_ (Plate VI., Figs. 2, 3, 4, 5),--(Description
based upon nine dorsals and two lumbar vertebræ.)

The centra are large, subtriangular, and slightly compressed; they
are opisthocœlous, but less so than in the _Proboscidea_. They
increase in size slowly but regularly from before backwards. In the
middle dorsal region they are excessively expanded laterally for the
posterior-costal attachments; but become less broad and higher as
they recede in the series. In the middle of the series the centra are
marked by a prominent hypophysial keel.

In the anterior dorsals the costal surfaces are developed almost
entirely upon the pedicles, and are two in number. These are very
large in about the sixth and seventh, and meet. They decrease in size
as they recede. In the middle region the posterior costal surfaces
are small, lozenge-shaped facets, and are developed upon thin lateral
projections of the centra.

The centrum of the last dorsal is heavy, resembling the centra of
the lumbar, from which it is distinguished by a single pair of small
costal surfaces, developed, half on the pedicles and half on the
centrum.

The neural spines are markedly smaller than those of the
_Proboscidea_ and _Rhinoceros_; in the anterior part of the dorsal
region the spines have the same angle as the corresponding ones in
_Mastodon_. The spines of the twelfth and thirteenth (approximately)
are much expanded at the ends and bifid; in the last dorsals they
are wide, straight, and very thin; in the lumbar region they are
short, stout, tuberous, and stand almost at right angles to the axis
of the vertebræ. The laminæ in the anterior part of the series are
long and thin, decreasing in length but increasing in thickness from
before backwards. The zygapophyses in the fore part of the dorsals
are mere flat facets on the laminæ; they increase in size and become
characteristic in the posterior part of the dorsal region. The
pre-zygapophyses of the last lumbar vertebra are very large, deeply
concave, and parallel with the axis of the column. The metapophyses
appear in the middle of the series, and regularly increase in size
to the last lumbar. From their appearance the pre-zygapophyses are
developed upon them.

The transverse processes present the most unique feature of the
vertebral column. In the anterior region they are long, wide, and
rugose, and in the same plane with the laminæ; they send directly
out wide, downward-curving projections. In the middle dorsal region
the transverse processes lose these thin projections, and become
heavy and subtrihedral, with a smooth facet on their lower face for
articulation with the tubercle of the rib; their upper face is here a
little twisted from the plane of the laminæ. In the posterior dorsal
region the transverse processes lose the facet for the articulation
with the tubercle of the rib, and become short and very thin,
pointing slightly backwards.

The lumbar transverse differ from those of the last dorsal in having
a median transverse ridge on their posterior face, and are directed
more vertically out.

The pedicles throughout most of the dorsal series are short, heavy,
and deeply notched behind. In the posterior dorsal region they become
longer and more slender, resembling almost exactly the pedicles of
the lumbar region.

_Sacral region._--The sacrum is composed of four vertebræ, three
true and one pseudo-sacral. The centra are extremely depressed, and
rapidly decrease in width and thickness from before backwards. The
first is shorter than the last lumbar, but much longer than the other
sacrals, which are subequal.

The face of the first is elliptical, and is nearly three times
the diameter of the fourth, longitudinally. The metapophyses are
exceedingly large and tuberous on the first; with wide, deeply
concave pre-zygapophyses developed upon them; in the other three the
metapophyses are rudimentary.

The transverse processes are long and wide in the first three; widest
in the first but thickest in the second; long and thin in the fourth.
The pleuropophysial segments of the true sacrals are very heavy.

The foramina enclosed by the transverse processes are large; and
have, on the internal side, their long diameter obliquely transverse
to the axis of the sacrum.

The inferior faces of the centra are slightly concave in the first
three. The first and fourth have slight hypophysial keels.

The neural canal is very wide and depressed in the first, but
decreases rapidly backwards, becoming extremely small in the last.

_Caudal region_ (Plate VI., Fig. 6).--(Description based upon the
first four.)

The centra of the caudal vertebræ are rather long, narrow, and
greatly depressed in the middle; they decrease in size gradually
backward. The pedicles and laminæ are short and thin, enclosing a
small neural canal. The neural spines point directly back, being
almost parallel with the axis of the centrum. They are slender and
tuberous at the extremity. The transverse processes are very long,
wide, and thin, thickened somewhat at the ends, and project directly
out; they decrease in size backwards. From the persistence of the
neural canal, and from its comparative size, it would seem as if the
tail was considerably larger than that of the elephant.

_Measurements of Vertebræ._

_Cervical region_ (Plate VI., Fig. 11).

                                                          M.
  Diameter of cervical (vertical)                        ·079
  Diameter of cervical (transverse)                      ·111
  Diameter of cervical (fore-and-aft)                    ·051
  Extreme length of prolongation of pedicles for
    zygapophyses                                         ·089
  Long diameter of vertebraterial canal                  ·040
  Width of pedicles                                      ·035

_Dorsal region_ (Plate VI., Figs. 2 and 3).

                                                          M.
  In anterior region: Diameter of centrum (fore-and-aft) ·075
  Diameter of centrum (vertical)                         ·062
  Diameter of centrum (transverse)                       ·142
  In posterior region (Plate VI., Fig. 3).: Diameter
    of last dorsal (vertical)                            ·087
  Diameter of last dorsal (transverse)                   ·110
  Average width throughout the series of neural canal    ·097
  Width of transverse process (anterior dorsal)
    (Fig. 2, Plate VI.)                                  ·075
  Length of lamina from prezygs. to post-prezygs.
    (Fig. 2, Plate VI.)                                  ·12
  Length of transverse process (middle dorsal).
    (Fig. 3, Plate VI.)                                  ·055
  Vertical length of anterior dorsal from tip of spine
    to hypapophysial keel                                ·183
  Width between inner margins of metapophyses
    (last dorsal)                                        ·172

_Lumbar region_--Last lumbar (Plate VI., Figs. 4 and 5).

                                                          M.
  Diameter of centrum (fore-and-aft)                     ·095
  Diameter of posterior face (transverse)                ·111
  Diameter of posterior face (vertical)                  ·078
  Extreme width between transverse processes             ·214
  Width between pre-zygapophyses                         ·110
  Length of neural spine from lamina                     ·060
  Vertical length from tip of spine to lower side of
    centrum                                              ·194

_Sacral region._

                                                          M.
  Length of sacral series                                ·264
  Transverse extent of sacral series                     ·298
  Diameter of first vertebra at free end (transverse)    ·109
  Diameter of first vertebra at free end (vertical)      ·072
  Diameter of first vertebra at free end (tore and aft)  ·070
  Diameter of last vertebra at free end (transverse)     ·053
  Diameter of last vertebra at free end (vertical)       ·031
  Diameter of neural canal at first vertebra
    (transverse)                                         ·100
  Diameter of neural canal at last vertebra (vertical)   ·018
  Long diameter of first transverse foramen
    (internal side)                                      ·076

_Caudal region_ (Fig. 6, Plate VI.).

                                                          M.
  Length of first four                                   ·252
  Diameter of centrum, first (fore-and-aft)              ·061
  Diameter of neural canal of first (transverse)         ·035
  Extent of transverse process in first                  ·085
  Extent of transverse process in fourth                 ·046
  Fore-and-aft width of transverse process of first
    in the middle                                        ·048

_Ribs._--Description based upon two perfect ones, and parts of four
more.

The ribs, as in _Dinoceras_, "resemble very much those of the
Mastodon." The capitulum has two convex facets, separated by a
narrow groove. The sternal end in one is very much expanded, but
less so in the other. The tubercle is small, and is situated upon
the prolongation of the lamelliform process for the intercostal
muscles. The angle is much sharper than in the corresponding ribs of
_Mastodon_.

_Measurements of Ribs._

                                                          M.
  Length of rib without curvature                        ·571
  Length of rib with curvature                           ·739
  Width of rib just below head                           ·049
  Width at muscular attachment                           ·063
  Vertical diameter of larger facet of capitulum         ·039

_Scapula_ (Plate VIII., Fig. 1).--The scapula is subtriangular,
with the pre-scapular border as base, and the apex half way up the
postscapular.

On the external side the pre-scapular fossa is concave
antero-posteriorly, and plane in the direction of its length; it is
very thin in the middle, but becomes heavier at the lateral border.
The postscapular fossa is larger and less concave; both fossæ, as
they approach the upper border, gain greatly in thickness.

The spine rises from the supra-scapular border, and extends to
within an inch from the glenoid cavity. It is decidedly antroverted;
thickest and highest near glenoid cavity; thinnest and lowest in the
middle, expanding again at its upper extremity; its acromio-scapular
notch is long and shallow. The acromion is rudimentary.

The coracoid process is a low, rugose tuberosity; the coraco-scapular
notch is short and low.

The internal surface of the scapula has a large, smooth median ridge,
extending the whole length of the bone, separating it into slightly
concave fossæ. About two thirds up, the median ridge sends obliquely
up two branches, forming a V, superimposed upon the main ridge; but
these disappear before they reach the upper extremity. The whole
inner surface is curved outward, presenting a concave appearance
throughout.

The glenoid cavity is deep, ovoid in form, with its greatest diameter
fore-and-aft, and its smaller end behind.

The resemblance between the scapula of _Uintatherium_ and that of the
_Proboscidea_ is more closely marked than in any other corresponding
bones. The chief points of similarity are: first, the subtriangular
shape; second, the same relative proportions between the fossæ;
third, the antroversion of the spine; fourth, the glenoid cavity
looking directly down. The marked points of difference may be summed
up as, first, in the dissimilar proportion of the glenoid cavity;
second, the great thickening of the spine at its upper and lower
extremities; third, in the high, shallow acromio-scapular notch;
fourth, in the longitudinal concavity of the internal surface.

_Measurements._

                                                          M.
  Extreme length of scapula                              ·42
  Extreme length of spine                                ·31
  Extreme thickness of spine at upper margin             ·098
  Extreme height of spine                                ·109
  Basal width of proximal end of spine                   ·032
  Basal width of distal end of spine                     ·030
  Basal width of middle part of spine                    ·011
  Length of glenoid cavity                               ·149
  Width of glenoid cavity                                ·096

_The Humerus_ (Plate VII., Fig. 1).--The humerus is short, but
excessively stout, twisted slightly on its axis; it decreases
gradually in size downward, with the smallest diameter about two
inches below the end of the deltoid ridge. The head is large,
hemispherical, and sessile, projecting very slightly out of the
axis of its shaft. The great tuberosity is heavy, but not high, and
is separated from the low lesser tuberosity by a shallow bicipital
groove.

The trochleæ are very nearly equal in size, directed obliquely to
the axis of the shaft, and are separated by a narrow groove, which
runs from the supra-trochlear fossa down and in, then back and up to
the anconeal fossa. The condylar tuberosities are large and rugose;
the external is the greater, and is directed antero-posteriorly. The
deltoid ridge is long and heavy, and extends nearly two thirds down
the shaft, branching out into two forks near its end. The supinator
ridge is short and rudimentary, differing in this respect entirely
from the great development found on the humerus of the _Proboscidea_.

The supra-condylar fossa is small, subcircular in form, and very
deep, it has the peculiarity of being placed above the external
condyle alone. The anconeal fossa is median in position and quite
deep.

_Measurements of Humerus._

                                                          M.
  Length                                                 ·63
  Smallest circumference of shaft just below deltoid
    ridge                                                ·288
  Greatest proximal circumference below greater
   tuberosities                                          ·45
  Width of trochlea on anterior side                     ·154
  Length of anconeal fossa                               ·071
  Width of anconeal fossa                                ·062
  Width of distal end at condylar tuberosities           ·23
  Length of deltoid ridge                                ·22
  Length of groove running from supra-trochlear to
    anconeal fossa                                       ·272

_The Ulna_ (Plate VII.. Fig. 2).--The ulna is long, heavy at both
ends, with a slender trihedral shaft that curves forward, and
decreases in size as it approaches the distal end. The proximal end
has its articular face for the humerus divided into three facets,
the vertical being long and extremely convex; the horizontal has the
pre-axial face the longer. The olecranon is very massive and rugose,
sending up on its external side a high, pointed projection; while
on the internal side, the olecranon becomes compressed and projects
inward; these tuberosities are separated by a wide, shallow groove
for the tendon. The distal articular face is large, single, and is
concave antero-posteriorly, and convex laterally. The styloid process
is very heavy.

_Measurements of Ulna._

                                                          M.
  Length of sigmoid notch                                ·089
  Width of sigmoid notch (horizontal face)               ·049
  Diameter of proximal end below articular face
    (fore-and-aft)                                       ·076
  Diameter of proximal end below articular face
    (transverse)                                         ·059
  Diameter of distal articular face (fore-and-aft)       ·061
  Diameter of distal articular face (transverse)         ·051
  Length of olecranon                                    ·112

_Pelvis._--The _ilia_ are greatly expanded laterally, with the iliac
surface concave and the gluteal surface nearly flat; thin in the
middle, they increase in thickness near the borders. The crests curve
regularly, and project above and beyond the sacrum, but do not bend
over the acetabula. The acetabular borders are only slightly concave;
the prominence for the attachment of the rectus muscle (extensor) is
low and V-shaped. The direct internal surfaces of the ilia, comprised
between the pubic and ischiatic borders, become deeply concave below
the ischiatic portion of the acetabulum. The sacral surfaces are wide
and triangular in shape; above they project beyond the sacral spines.

The ilio-lumbar angle is about 110°. The ischium is, short; a section
of it, as it leaves the acetabulum, is subtriangular; but immediately
it becomes flattened fore-and-aft throughout its plane of 90° to the
axis of ilium; then verging toward the pubic symphysis it becomes
small. The tuberosity of the ischium is small and directed up.

The pubis, as it leaves the acetabulum, is sub-cylindrical, after
this it is flattened in the same plane with the ischium. The bone
as a whole is short, thin, and slightly curved on its own axis; its
smallest part makes up the pubic symphysis, which is short. The
thyroid foramen is a large oval, with its long diameter parallel to
the axis of the ischium.

The acetabulum is large, subcircular, and deep, with prominent
borders; especially the iliac, which is produced on its external
extremity into a point; the ischiatic is deeply notched. From the
wide ligamentous pit in the centre there runs a deep groove part way
down the antero-external side of the ischium.

The anterior opening of the pelvis is a wide oval, with its longest
diameter transverse.

_Measurements of Pelvis._

                                                          M.
  Transverse diameter of pelvis, including sacrum       1·171
  Long diameter of ilium (from lower margin of the
    crest to sacral surface)                             ·440
  Short diameter of ilium (from acetabulum to upper
    margin of crest)                                     ·393
  Length of acetabular border                            ·125
  Length of ischium                                      ·220
  Width of ischium at tuberosity                         ·124
  Length of pubis                                        ·196
  Greatest width of pubis                                ·061
  Smallest width of pubis                                ·027
  Long diameter of acetabulum                            ·139
  Short diameter of acetabulum                           ·118
  Long diameter of thyroid foramen                       ·094

_The Femur_ (Plate VIII., Fig. 4).---The femur is short, with a
small oval head, strongly compressed fore-and-aft. It is less out
of the axis of shaft than in _Proboscidea_, and has no pit for the
ligamentum teres. The shaft is straight and simple, much compressed
transversely at the proximal extremity, becoming sub-cylindrical
below.

The great trochanter is heavy, rugose, and strongly recurved; it is
separated from the shaft by a wide and deep digital fossa. The second
trochanter is a mere rudimental tuberosity. The condyles are nearly
of an equal size, very convex, and are divided by a deep popliteal
groove.

The condylar tuberosities are low, the internal sends obliquely a
ridge three inches long, up and across the axis of the shaft at an
angle of 45°, that forms the upper boundary of the popliteal space.

The front part of the trochlear faces for the patella are gone in our
specimen.

_Measurements of Femur._

                                                          M.
  Greatest distal diameter across condyles              ·178
  Length of condyles                                    ·079
  Transverse diameter of shaft six inches above
    distal end                                          ·121

_The Tibia_ (Plate VIII., Fig. 2).--The tibia is short, straight, and
simple, slender in the middle, but much expanded at the extremities.
The proximal end is especially massive, with deeply concave articular
faces; the internal cotylus is the larger, and has its greatest
diameter fore-and-aft, directly at right angles to the greatest
diameter of the external.

The cotyli are separated by a smooth ridge, that is highest at its
posterior termination. The tuberosity is high and massive, with a
wide depression on its top for the reception of the ligament of the
patella; the sides are deeply pitted by venous foramina. A section of
the shaft at the lower part of the tuberosity would be subtriangular;
while below it becomes more cylindrical, as it becomes smaller,
reaching its shortest diameter about three fifths down the shaft.
Below this it expands and forms the large subcircular distal end.
The articular face is concave, with a slight, smooth ridge running
fore-and-aft on its internal side. The malleolus is broad and low.

The _fibula_ is distinct, but very slender; its proximal end has a
small circular face, which articulates with the tibia on a facet
developed on the bottom of a projection of the tuberosity; the distal
end is much flattened, but enters into the ankle-joint.

_Measurements of the Tibia._

                                                          M.
  Transverse diameter of proximal articulation           ·158
  Longitudinal diameter of proximal articulation         ·123
  Smallest circumference of shaft                        ·16
  Greatest distal circumference above the articular face ·308
  Diameter of distal articulation longitudinally         ·082
  Diameter of distal articulation transversely           ·130
  Width of tuberosity below pit for ligament of the
    patella                                              ·075


Uintatherium princeps, _sp. nov._

Established on several portions of the head, vertebral column, and
the limbs.

This species may readily be distinguished from the last by its
larger size, the broad nasals with small tuberosities, the stronger
zygomatic arches, and the sub-cylindrical centra of the dorsal
vertebræ.

The _nasals_ are broad and flat for some distance behind the
tuberosities. Although the animal was not adult, the nasal suture
is almost obliterated, and is visible only on the inferior surface;
in this respect it is very different from the _U. leidianum_, in
which the suture persists throughout life; as is shown by the type
specimen, which was past maturity. The tuberosities of _U. princeps_
are lower, broader, and more everted than in the preceding species;
are not divided by a groove, but united together by a low rounded
ridge, to which the surface of the nasals gradually rises from
behind. The portion of the bones anterior is short, stout, and
projects horizontally.

The _median_, or _maxillary_, _projections_ are apparently short and
everted; they are somewhat compressed antero-posteriorly, and enlarge
rapidly downwards. They are transversely oval in section.

The _posterior_, or _parietal_, _projections_ are different from any
that we have yet seen. They are subtrihedral at base and flattened
antero-posteriorly above. The upper margin is regularly arched,
and is the thinnest portion of the process. The posterior face is
perfectly flat, and the parietal crest makes a sharp angle with it,
rising lower down than in _U. leidianum_; the frontal crest is also
lower down than in that species, and the anterior face is strongly
convex. The internal margin is rounded and straight, and does not
show the longitudinal groove marked in the last species.

The _frontal_ has the eminences and depressions common to the members
of the genus; but the superciliary ridge is unusually sharp and
sinuous in outline.

The _squamosal_ is short, stout, and high; is but slightly curved
outwards, but apparently projects somewhat downwards. The malar
articulation is broad and flat, indicating the heaviness of that
bone. As a whole the zygomatic arch is stronger, and probably
shorter, than in _U. leidianum_.

The occipital condyles are proportionately rather small; they are
placed on a long neck and project downwards. They are strongly convex
from above downwards, but scarcely at all so from side to side. The
internal border is slightly emarginate.

The _dorsal vertebræ_ are of about the same proportionate length
as in _U. leidianum_, but are higher and wider; and the centra are
subcircular in section, slightly contracted in the middle. The costal
surfaces are wide and deep, and vertically oval in shape; they are
placed partly on the centra and partly on the neurapophyses. The
transverse processes are short, stout, and tuberous, and raised
high above the centrum. There is a deep notch at the posterior
edge of this process, at its junction with the neurapophysis. The
neurapophyses are trihedral, somewhat low, and very stout, forming a
wide neural canal.

The _ulna_ (Plate VII. Fig. 2) is thick, with a long and rugose
olecranon. The shaft is long and stout; it shows a distinct medullary
cavity. The distal end is small, and shows a low, heavy, styloid
process.

A _metacarpal_ resembles the corresponding bone in _Dinoceras_,
but is rounder and less rugose. There are two faces for carpal
articulations, which meet at an open angle.

_Measurements._

                                                          M.
  Breadth over nasal tuberosities                        ·132
  Length of nasal tip (anterior to tuberosities)         ·033
  Circumference of maxillary projection near the tip     ·208
  Vertical diameter of squamosal                         ·058
  Transverse diameter of ditto at malar articulation     ·045
  Length of centrum of dorsal vertebræ                   ·070
  Height of ditto                                        ·083
  Breadth of ditto below costal surfaces                 ·097
  Breadth of pedicle                                     ·058
  Length of transverse process                           ·056
  Extreme breadth of transverse process                  ·061

Found at Henry's Fork.


Uintatherium robustum. Leidy.

Cont. to Ext. Vert. Faun., p. 96.

A fragmentary skeleton from Henry's Fork.




RODENTIA.


PARAMYS, Leidy.

"Extinct Vertebrate Fauna of the Western Territories," vol. i.
Hayden's Surveys, p. 109 _et seq_.

This genus of the gnawers is very closely allied to the squirrels and
marmots. Dr. Leidy sums up the generic characteristics of the teeth
thus:

"The four lower molars are proportionately narrower than in squirrels
and marmots, the fore-and-aft exceeding the transverse. The crowns
are short, square, tuberculate, and enamelled.

"The lower jaw is proportionately shorter and deeper than in most
known rodents; the reduction in length being mainly due to a less
development of that part of the bone in advance of the molars.
To compensate for the difference in length, and to make room to
accommodate the incisors, these teeth reach further back than usual.

"The acute edge of the hiatus between the molars and incisors is
almost on a level with the alveoli, of the teeth, instead of forming
a deep concave notch, so conspicuous a feature in the jaws of the
gnawers generally."

_Species known._--

             { Paramys delicatus, Leidy.
  Loc. cit.  { Paramys delicatior, Leidy.
             { Paramys delicatissimus, Leidy.
               Paramys robustus, Marsh.

  Am. Journ. Sc. v. iv., p. 218.


Paramys superbus, _sp. nov._

Established on a single lower incisor.

The species indicated by this specimen is the largest of the genus as
yet known. The tooth is subtrihedral in section, is stout, and shows
but little curvature. The anterior and lateral faces are broad, and
the under margin to which the sides converge, is narrow. The enamel
is thick and is inflected so as to cover a small portion of the sides
as well as the front.

_Measurements._

                                                          M.
  Transverse diameter of crown                           ·0062
  Fore-and-aft diameter of crown                         ·007

Found at Cottonwood Creek.




AVES.


The expedition collected parts of four species of birds; a feather
from Florissant Col. the distal ends of a humerus, and a femur and a
portion of the shaft of an ulna (?) from the Bridger beds, but they
are all too uncharacteristic for classification or description.




REPTILIA.


CROCODILIA.

CROCODILUS.


Crocodilus aptus, Leidy.

Contributions to Extinct vertebrate fauna of the Western Territories,
p. 126.

Henry's Fork.

Crocodilus Grinnelli, Marsh.

American Journal of Science and Arts, vol. i., p. 465.

From Cottonwood Creek.

Crocodilus Elliotii, Leidy.

Cont. to Ex. Vert. Fauna, p. 126.

Represented by a perfect skull, and several vertebræ.

This fossil exhibits a form of skull which shows characters of both
crocodile and alligator; the latter to a less marked degree. That it
properly belongs to the former genus is shown by the notch in the
upper jaw which receives the canine of the lower.

The entire skull is remarkably flat on its upper surface, the face
and cranium being nearly in the same plane without the descent at the
frontals usual in these reptiles. The jaw is deeply notched at the
sutures between the maxillaries and pre-maxillaries, and the second
maxillary notch is well marked. All the bones of the upper surface of
the head are deeply pitted.

The borders of the cranium are rounded as they approach the orbits;
the superior temporal orifices are almost perfectly circular,
the fore-and-aft diameter exceeding the transverse by only one
millimetre. This effect may, in some degree, be due to distortion.

To give a more detailed account of the several elements of the skull,
we take up first the _basioccipital_. This bone is remarkably long
and straight, tapers gradually downwards, and becomes quite narrow
at the distal end. It is smooth throughout, and exhibits no rugose
muscular attachments, such as are sometimes seen in other members of
the order. The condyle is large and nearly spherical, but with median
groove distinctly marked. In size and shape it is more like that of
the alligator than of the ordinary crocodile, but it is somewhat
different from either. It differs from the former, in not having so
long a neck distinctly marked by a constriction; and from the latter,
in not having additional articular faces on each side of the condyle
proper. As far as can be judged, no portion of it is formed by the
exoccipitals. Below the condyle the basioccipital is perforated by
two small vascular foramina; the spheno occipital canal occupies the
usual place, and is very large.

The _exoccipitals_ are large, of very great width, but rather low
from above downwards. The position of the foramina which perforate
these bones is peculiar; it resembles more the arrangement seen in
the skull of the alligator than in that of the crocodile, but it has
an additional foramen. There are, then, two small venous foramina
near the condyle; while along the lateral margin of the occiput,
are placed in a vertical line the foramina for the hypoglossal and
pneumogastric nerves, and the internal carotid artery. The foramen
for the facial nerve, etc., is situated in the usual place, and is of
the usual size. The foramen magnum is heart-shaped, low, wide above,
contracting below. The paroccipital processes are long and slender,
and project strongly backwards.

The _supra-occipital_ is very small. It shows to some extent on
the upper surface of the skull, wedged in between the parietals.
As a whole, the occiput is of remarkable shape: it is perfectly
vertical, as in all other crocodilians; is remarkably high from
above downwards, and is very broad at top, becoming extremely narrow
distally. This latter feature is owing to the peculiar shape of the
pterygoids; which, when viewed from behind, do not appear to reach
the basioccipital.

The _basisphenoid_ is so destroyed by crushing, that nothing can be
said of its shape or of its foramina. It was, however, evidently
very stout. The alisphenoid is large and smooth and is not ridged;
the _foramen ovale_ is small, and is not produced into an anterior
notch. The suture between the alisphenoid and the pro-otic are quite
distinct, but the latter is so firmly anchylosed to the quadrate that
its limits are indeterminable. None of the other periotic bones are
visible.

The _quadrate_ is very long and broad. In shape it resembles the
corresponding bone of the alligator, but is somewhat broader. The
lower surface is divided into two unequal parts by a conspicuous
ridge, which runs to within an inch of the articular surface. This
surface has a more decidedly grooved or trochlear appearance than in
the common crocodile; but not to the same degree as in the specimen
described by Dr. Leidy. It is more like the Mississippi alligator in
this respect than any living species of which we have specimens.

The _pterygoids_ are of peculiar shape; they are long, slender, and
pointed, and meeting the basioccipital on the median line in front,
they project downwards and backwards. Their posterior border is very
deeply emarginate, so that they seem to have no connection with
each other, or with the basioccipital; instead of having the broad,
plate-like appearance of these bones in recent species. The suture
between these on the palatal surface is long; and the processes of
the pterygoids, which bound the posterior nares, are long and stout.
The posterior nares have the position which they take in the recent
species; they are visible in the occipital surface, and are directed
backwards as well as downwards. They are rather small, and appear
to have no septum between them, but this cannot be said with any
certainty.

The _transpalatine_ is also somewhat peculiar in shape; the process
which joins the pterygoid is of great length, being nearly as long
as that bone. The other limbs are more normal in length. The three
processes are connected at the usual angle.

The _palatals_ are long and narrow, becoming wider anterior to the
foramina. The suture with the maxillaries is rounded, and there are
no forward processes as in the true crocodiles; but at the same time,
these bones are not of the shape exhibited in the alligators. The
palatal foramina are of immense length; they are more than one third
as long as the entire bony palate. Their width is also considerable.

The _maxillaries_ are long and very broad; the alveolar border is of
about the same shape as in the crocodile, but less decidedly sinuous;
and the posterior part passes in below the alveolus of the lower
jaw. The convexity of the upper surface of the maxillaries is not
so well marked as in the true crocodiles. It is nearly as flat as
in the alligator. The palatine plates of the maxillaries are short,
broad, and nearly flat, arching slightly to form the alveolus, and
perforated along this border by rows of foramina.

The _premaxillaries_ are very short; they curve strongly outwards
from the notch and enclose the large anterior narial opening, which
is distinctively crocodilian (as distinguished from other genera)
in shape. The muzzle ends quite sharply. The palatine processes are
short and convex in both directions, and the incisive foramen is
heart-shaped. The alveolus is quite regular in outline; it is pitted
in front for the first mandibular teeth, but there is no perforation
for them.

The teeth are short, stout, compressed so as to form cutting-edges,
and are somewhat obtuse. They are finely striated from base to tip.
The premaxillary held four teeth; these are all broken off, but from
their fangs it appears that they formed an uninterrupted row, and
were subequal in size. The maxillary accommodated fifteen teeth, of
which the fifth is the largest, and forms a very prominent canine.
The posterior maxillary teeth are proportionately larger, and more
equal than in either crocodile or alligator.

The _nasals_ are rather broad; they send processes into the
anterior narial opening, which tend to divide it, but this division
was probably not complete. The limits of the _prefrontals_ and
_lachrymals_ are so obscure as to preclude description.

The _frontals_ are long and very narrow, though wider than in the
alligator. They are smooth and flat, exhibiting no concavity on top.
They expand considerably at the posterior part of the orbit, at the
sutures with the post-frontals. These bones are long, stout, and
curved very strongly outwards.

The _mastoids_ are of remarkable size; they project far backward
along the tympanic, and encroach largely upon the occipital region.
It is partly owing to this that the occiput is so high.

The _parietals_ are short, and very narrow between the temporal
orifices, behind these they expand considerably. The orbits are large
and of irregular shape.

The _malar_ is long and rather slender.



_Measurements._

                                                          M.
  Length from occipital border to end of muzzle          ·455
  Breadth of cranium at postorbital angles               ·0935
  Breadth of cranium between temporal orifices           ·019
  Breadth of forehead between orbits                     ·036
  Breadth of temporal orifices                           ·037
  Fore-and-aft diameter of the same                      ·038
  Fore-and-aft diameter of the orbits                    ·073
  Length of face in advance of the orbits                ·3055
  Breadth of face outside of the fifth maxillary tooth   ·176
  Breadth of muzzle as formed by premaxillaries (about)  ·114
  Breadth of muzzle at notch for canine                  ·093
  Length of premaxillaries to notch                      ·080
  Estimated length of entire alveolar border             ·283
  Breadth of articular surface of quadrate               ·059
  Vertical height of occiput                             ·124
  Vertical diameter of foramen magnum                    ·016
  Transverse diameter of foramen magnum                  ·025
  Vertical diameter of condyle                           ·023
  Transverse diameter of condyle                         ·028
  Length from palatine foramen to end of pterygoid       ·120
  Length of palatals                                     ·1295
  Length of palatine foramen                             ·142
  Greatest breadth of palatine foramen                   ·051
  Length of bony palate from incisive foramen to
    posterior nares                                      ·350

The _mandible_ is long, rather shallow, but very thick. The symphysis
is very long, extending as far as the seventh tooth. The chin is
quite sharp, but becomes broad, as the rami diverge quite rapidly.
The alveolar border is rounded and comparatively straight, the median
enlargement of the dentary is in thickness rather than in height.
The two rami diverge at an angle which is more open than in the
true crocodiles, and less so than in the alligator. The mandibular
foramen is smaller than in the latter genus, but corresponds with it
in position; it has its long diameter parallel with, and not oblique
to, the alveolus. The mandibular fossa is extremely large and deep.
The splenial is long and stout, ends obtusely, and does not reach
the symphysis. The articular cavity is broad from side to side, but
rather shallow; it is not divided into two distinct facets as in the
alligator. The post-glenoid process is very stout; it projects but
slightly upwards, less so than in either crocodile or alligator. It
has no median ridge as in the former genus, and is tuberous at the
end.

The teeth are much like those of the upper jaw, but are somewhat
sharper and more conical; they are not recurved, and have no distinct
constriction, as is found in most of the recent species. There are
about eighteen teeth to each ramus; the first is large and sharp, and
is followed by two small ones and then by the canine. The remaining
teeth do not exhibit any great differences of size.

_Measurements._

                                                          M.
  Length of rami (straight)                              ·618
  Width of lower jaw outside of glenoid cavities         ·316
  Length of symphysis                                    ·110
  Width of jaw at second enlargement                     ·057
  Depth at oval foramen                                  ·073
  Greatest width at symphysis                            ·110
  Space occupied by teeth                                ·340
  Breadth of glenoid cavity                              ·072
  Length of post-glenoid                                 ·065

_Vertebræ._

_Cervicals._--The centra are long and nearly cylindrical, expanding
slightly near the anterior face. The hypapophyses are short and
broad; they project forwards, and are somewhat compressed. The
vascular foramina correspond in size and position to those of
the alligator. The neural canal is small and subcircular, having
comparatively short but very stout neurapophyses, which are
perforated behind the diapophyses. These are short and stout, and are
developed from the neurapophyses alone. The zygapophyses are long
and flat; the anterior ones project almost vertically. The neural
spines are stout, and of greater antero-posterior extent than in the
alligator.

_Dorsals._--A few of the anterior dorsals have strong hypapophyses.
The centra of all are long and stout. The neural canal is smaller
than in the cervical region; it has strong neurapophyses, which
develop long and depressed diapophyses. The neural spines are low
and broad. The zygapophyses are developed on the laminæ, and do not
project upwards as in the cervical region.

The _lumbars_ are much like the dorsals, except that they are longer,
and have very large and depressed diapophyses, which project somewhat
upwards.

_Measurements._

                                                          M.
  Length of centrum of a posterior cervical              ·049
  Height of neural canal                                 ·015
  Fore-and-aft diameter of neural spine                  ·023
  Length of diapophysis                                  ·023

_Dorsal._

                                                          M.
  Length of centrum                                      ·0555
  Length of hypapophysis                                 ·018
  Fore-and-aft diameter of neural spine                  ·030

_Lumbar._

                                                          M.
  Length of centrum                                      ·057
  Fore-and-aft diameter of neural spine                  ·0285
  Diameter of diapophysis                                ·029

The dermal scutes are long ellipses, deeply pitted on one side, but
without a trace of a keel. Their edges show no signs of sutural union.

The bones described indicate a reptile about fifteen feet long. They
were found near Smith's Fork, Wyoming.


Crocodilus parvus, _sp. nov._

A small reptile represented by sixteen vertebræ and a portion of the
pelvis.

The _cervicals_ have short centra, with very deep articular cups
and hemispherical heads: the latter have a prominent rim around the
base. The hypapophyses are short, stout, and very nearly vertical
in direction; the sides of the centra are channelled by a deep
vertebraterial canal; the parapophyses are developed very low down,
and are very prominent. The diapophyses are developed partly from the
centra and partly from the neurapophyses; they are stout and very
short. The facets for the ribs are developed in the usual place.
The neural arch is rather high, and forms a small, narrow canal;
the proportions of the neurapophyses and neural spines are about as
in _Alligator mississippiensis_, but the zygapophyses are not so
prominent.

The _dorsals_ show a considerable increase in size over the
cervicals; the centra become elongate, and the articular cups
shallower and transversely oval. Several of the anterior vertebræ
retain large hypapophyses. In the dorsal region the diapophyses are
developed from the neurapophyses alone, and at a considerable height
above the neuro-central suture; they are long and depressed. The
zygapophyses and neural spines present no peculiarities of structure.

In the _lumbar_ region the vertebræ regain their cylindrical form,
and become still more elongate; but the cups are comparatively
shallow and the heads low; there is no distinct shoulder. The
neural canal is small, with low, broad neurapophyses, from which
are developed very broad and depressed diapophyses, which project
outwards in a horizontal plane. The neural spines are thick, and
broad antero-posteriorly, but are so broken that their height cannot
be determined.

In both dorsal and lumbar region the neurapophyses are deeply notched
on their posterior edges, and close to the neuro-central sutures, for
the passage of the spinal nerves.

The _ilium_ is very high compared with most crocodiles; its vertical
diameter is considerably more than half of the antero-posterior
diameter. The construction of the bone is very much like that in the
modern _Crocodilia_; but the suprailiac border is more regular, and
the anterior tuberosity is not so thick or so much everted as in
these forms. The acetabulum is small, shallow, directed downwards
and outwards, and situated considerably forward of the median line.
The iliac surface is smooth, but very irregular, being very deeply
concave above the acetabulum, and convex behind it. The sacral
surface is rugose, rises above the sacrum, and shows attachments for
two sacral vertebræ. Thus the construction of the entire pelvis shows
but very little variation from the modern type.

_Measurements._

                                                          M.
  Antero-posterior diameter of ilium                     ·095
  Vertical diameter of ilium                             ·061
  Antero-posterior diameter of acetabulum                ·029
  Length of centrum of third (?) cervical vertebra
    (from edge of cup to tip of ball)                    ·032
  Height of neural canal, third (?) cervical             ·0095
  Length of hypapophysis of third cervical               ·0085
  Length of centrum of a posterior dorsal                ·040
  Length of diapophysis (about)                          ·032
  Length of centrum of a lumbar                          ·046
  Vertical diameter of a lumbar                          ·029
  Breadth of neurapophysis of a lumbar                   ·027


Crocodilus heterodon, Cope.

_Alligator heterodon_, Proc. American Philosophical Society, 1872, p.
544.

Represented by a single tooth from the posterior part of the
mandibular series. It agrees very closely with the corresponding
tooth of _Alligator mississippiensis_, but presents some differences.
The crown is very low, obtuse, and finely striate; it is compressed
and shows a cutting-edge. Its longest diameter is fore-and-aft; both
this and the transverse diameter are proportionately greater than in
the modern species. The constriction of the neck is very decided; the
fang is large, and especially thick.

_Measurements._

                                                          M.
  Fore-and-aft diameter of crown                         ·010
  Transverse diameter of crown                           ·007
  Vertical height of crown


Crocodilus clavis, Cope.

U. S. Geol. Survey of Terrs. 1872, p. 612.

This species is indicated by the remains of a crocodilian larger
than _Crocodilus Elliotii_, but very different from it. The pitting
of the dermal scutes, and of all the cranial bones, is deeper than
in any other of the Bridger crocodilians in our possession, and very
strongly resembles that in _Alligator mississippiensis_.

The _mandible_ has a long symphysis, and the alveolar border shows
the sudden deep depression just behind it, which is so marked in
the ordinary alligator. The rami, however, do not diverge at such an
open angle. The jaw is very stout, and is deeper and thinner than
in _Crocodilus Elliotii_; and is of about the same proportionate
thickness, but deeper than in the alligator. The splenial ends
obtusely, and approaches the symphysis somewhat more closely than in
the alligator, but does not enter into its formation. The teeth are
stout and obtusely conical, not striate, and implanted very close
together; they exhibit about the same alternation of size as do
those of the alligator. What appears to be the canine is small; it
is preceded by a much smaller, and succeeded by a slightly smaller
tooth. The dermal scutes are quadrate in shape; they are deeply and
irregularly pitted, and have a low but distinct longitudinal keel;
they are suturally united by their lateral borders.


CHELONIA.

The Bridger beds have yielded a great abundance and variety
of land, marsh, and fresh-water chelonians. They present much
variation of form and size; and, owing to the great pressure in the
strata, scarcely any two specimens of the same species are alike;
occasionally, however, an undistorted specimen is obtained.

The most abundant remains of turtles are those of a species of the
recent genus _Emys_, which are found in all the beds, and are,
perhaps, the commonest fossils of the basin. The genera _Trionyx_ and
_Hadrianus_ (_Testudo_, Leidy) follow next in order.


HADRIANUS, Cope.

Resembles _Testudo_ in form, but has two analscuta, as have most
_Emydidæ_.


Hadrianus allabiatus, Cope.

U. S. Geol. Survey of Territories, 1872, p. 630.

Represented by two ungual phalanges which resemble the claws of
_Testudo_, but are proportionately shorter, broader, and not so
pointed at the ends. They are oval in section, both longitudinally
and transversely; the articular faces are deep and subinferior.

From Henry's Fork.


Hadrianus octonarius, Cope.

Geol. Survey of Terrs., 1872. p 630.

Represented by the right humerus of a large individual.

This bone is intermediate in character between the corresponding
bones of _Testudo_ and _Emys_. The head is longer and narrower than
in the former genus; it is implanted on a short, distinct neck,
and is strongly convex in both directions. The articular surface
extends to the base of the internal tuberosity. The tuberosities,
especially the external one, are very large and thick. The external
rises above the head, and resembles that of _Emys_ in shape. The
fossa separating the tuberosities is comparatively narrow. The shaft
is much like that of _Emys_, but is somewhat more strongly curved;
not so much, however, as in _Testudo_, and the distal end is not so
much flattened. The anconeal fossa is wider and deeper than in either
genus. The trochlea is broad, and divided by an obscure groove into a
small and convex radial face, and a nearly plane (transversely) ulnar
face. The condyles are prominent and rugose.

Found near Dry Creek.


EMYS.

Emys wyomingensis, Leidy.

Cont. to Ex. Vert. Fauna, p. 140.

Represented by six perfect shells from Cottonwood and Dry Creeks, and
Henry's Fork, and a shoulder girdle from Cottonwood Creek, which is
provisionally referred to this species.

This species, when adult, was upward of a foot in length, and in
the composition of the shell, number of scutes, etc., resembled the
living species of the genus.

_The Shoulder Girdle_ has the form characteristic of the _Emydidæ_,
but presents some peculiarities. The scapula is short, not being
as long as the coracoid, and is not so straight or cylindrical as
is usual in _Emys_; but is compressed, and somewhat recurved, and
tapers towards the upper extremity, which is marked by a smooth
rounded facet for the cartilaginous supra-scapula. The precoracoid
is long, sub-cylindrical at its origin, but becomes broad and flat
distally; at the extremity it is longitudinally striated. The
proximal end is flexed forward at an obtuse angle, and is expanded to
form the long suture with the scapula and coracoid. It contributes
considerably to the glenoid cavity. The coracoid is remarkably long,
and after leaving the sutures with the other elements of the girdle,
becomes very broad and thin. This is most marked distally. The
anterior border is thickened, and the bone is slightly concave on
both surfaces.

The three parts of the shoulder girdle are united by distinct bony
symphyses; they differ from some of the modern species, in which
there is only a ligamentous union between the coracoid and the other
parts. It presents a further difference in the long and slender neck
which is formed by the flexing of the precoracoid, and in the shallow
and subcircular glenoid cavity. The short scapula and long coracoid
would indicate a species with a low, broad carapace, as was probably
the case in _E. wyomingensis_, though much difficulty has been
experienced in determining this point, owing to the distortion of the
specimens.

_Measurements._

                                                            M.
  Length of neck to point between coracoid and precoracoid ·0345
  Length of coracoid (about)                               ·133
  Length of precoracoid                                    ·114
  Length of scapula (about)                                ·126


BAENA, Leidy.

Baena undata, Leidy.

Cont. to Ex. Vert. Fauna, p. 160.

Three nearly perfect shells of different ages, from Dry and
Cottonwood Creeks.


TRIONYX, Geoffr.

Trionyx uintaensis, Leidy.

Cont. to Ex. Vert. Fauna, p 176.

Cottonwood Creek.




PISCES.


TELEOSTEI.



TELEOCEPHALI.

_CYPRINODONTIDÆ._

"Head and body covered with scales; barbels, none. Margin of the
upper jaw formed by the premaxillaries only. Teeth in both jaws;
upper and lower pharyngeals, with cardiform teeth. Dorsal fin
situated on the hinder half of the body." (Günther.)


TRICOPHANES, Cope.

U. S. Geolog. Surveyor the Terrs., 1872, p. 641.

Having secured a very perfect specimen of this genus, we are enabled
to complete the definition of its generic characters. We give, then,
Professor Cope's definition, with some emendations and additions:
Dorsal and anal fins short; ventral fin sometimes beneath and
sometimes in advance of the dorsal. The premaxillary forms all of the
superior arcade of the mouth, which has a wide gape, opening back
behind the orbit. This bone has a row of long, slender, recurved,
and subequal teeth implanted in it. The dentary is stout, and has a
few small teeth. The branchiostegal rays are six in number, and are
rather wide. The preoperculum IS serrate. The operculum is ridged on
top. The anterior vertebræ are unmodified, and the centra are not
elongate. A strong acute spine supports the dorsal, and a similar one
the anal fin. There is a long post-clavicle, which may or may not
extend to the base of the ventral parallel with the femur. The femur
is long and furcate; the external part straight and reaching to the
clavicle; the internal curves to meet the corresponding portion of
its fellow. The ventral radii are eight in number, and the caudal
fin is furcate. The scales are peculiar, and characteristic of the
genus. They are very thin, and have borders fringed with long,
close-set, bristle-like processes. This genus includes as yet only
three species: _T. hians_, from Osivio, Nev.; and _T. foliarum_ and
_T. Copei_, from Florissant, Col.


Tricophanes Copei, _sp. nov._

Vertebræ D. 12, C. 18, Radii D. 14, A. 8, V. 8, C. 41, P. 5 only
visible, not all preserved. The dorsal fin is long, and projects
beyond the beginning of the anal fin; the mouth is terminal, and
the muzzle rather sharp. All the bones of the skeleton are very
slender; and this is especially true of the ribs, which are not as
thick as the interneurals. The neural and hæmal spines are short
and slender. The origin of the dorsal is nearer to the muzzle than
to the caudal; though, as a whole, the fin is on the hinder half of
the body. There are no interneural spines in front of the dorsal
fin; those supporting the fin are short, slender, and without the
laminar expansions found in _T. foliarum_. The caudal fin consists of
numerous jointed rays, which are supported by the neural and hæmal
spines of the last three vertebræ. The scales are small, and exhibit
the peculiarities of the genus, but the rows are too imperfect to be
counted.

_Measurements._

                                                            M.
  Total length (straight)                                  ·0935
  Length of head                                           ·018
  Length of vertebral column                               ·055
  Length of caudal fin                                     ·024
  Length of dorsal spine                                   ·011
  Length of anal spine                                     ·009
  Depth of head posteriorly                                ·016
  Length of mandibular ramus                               ·010
  Length to dorsal fin (from muzzle)                       ·033
  Length of dorsal fin                                     ·0135
  Depth of body at middle of dorsal fin                    ·017

Found in the insect beds at Florissant, Col.


_CATOSTOMIDÆ._

Body covered with scales; head naked; margin of upper jaw formed by
the premaxillaries; mouth toothless. Pharyngeal teeth in a single
series, and exceedingly numerous and closely set. Dorsal fin elongate
and opposite the ventrals. Anal short, or of moderate length.


AMYZON, Cope.

U. S. Geolog. Survey of the Terrs., 1872, p. 642.

Allied to _Bubalichthys_. Dorsal fin elongate, with a few fulcral
spines in front. There are three broad branchiostegals. The vertebræ
are short, and the hæmal spines of the caudal fin are distinct and
rather narrow. The teeth are arranged comb-like, are truncate,
and number from thirty to forty. The dentary bone is slender and
toothless, and the angular is distinct.


Amyzon commune, Cope.

U. S. Geolog. Survey of Terrs., 1873, p.

Represented by several fine specimens from near Castello's Ranch, Col.


_SAURODONTIDÆ._

For a very complete definition of this family, see Cope's Cretac.
Vert., p. 183.


PORTHEUS, Cope.

Cretac. Vert., p. 189 et seq.

"Teeth subcylindric, without serrate or cutting edges, occupying
the maxillary, premaxillary, and dentary bones; size, irregular;
premaxillary, median maxillary, and dentary much reduced. No foramina
on inner face of jaws. Teeth on the premaxillary reduced in number.
Opercular and pre-opercular bones very thin. Cranial bones not
sculptured."


Portheus thaumas (?), Cope.

Loc. cit. p. 196.

Maxillary large, teeth three; third mandibular small, without cross
groove in front of it.

A single tooth from the cretaceous sandstone of Cement Gulch, Col.,
is provisionally referred to this species; the reference cannot be
certain, as the specimens described and figured by Professor Cope
have the crowns of the teeth broken. The tooth is not so long as the
largest tooth of _P. molossus_, but is of proportionately greater
diameter and not so straight. It is conical and recurved, and shows
two very obscure cutting-edges, which divide the crown into two
unequal faces. It has faint longitudinal striations on all sides, and
the apex is sharp.

_Measurements._

                                                            M.
  Fore-and-aft diameter at the base                       0·613
  Height of crown                                         0·020


NEMATOGNATHI.


_SILURIDÆ._

"Skin naked, or with osseous scutes, but without scales. Barbels
always present; maxillary bone rudimentary, margin of the upper jaw
formed by the premaxillaries only. Suboperculum absent; adipose fin
present or absent." (Günther.)


RHINEASTES, Cope.

U. S. Geol. Survey of the Terrs., 1872, p. 638.

A genus allied to the recent _Ichtælurus_ but differing in the
inferior grooving of the vertebræ and in the rough exostoses of the
cranial bones. It differs from _Phareodon_ in having the usual band
of bristle-like teeth on the dentary.


Rhineastes ---- ?

Represented by a portion of the dentary and hyomandibular bones of a
large cat-fish from Bridger Butte.

The dentary is broad and shallow, grooved below, and deeply striated
on the external face. As much of it as is preserved is straight.
The teeth are small, subequal throughout, and very numerous. The
hyomandibular is broad and thick, and has a striated surface. The
condyle is peculiar in having two separate articular faces above and
below, one convex and the other flat.


GANOIDEI.

CYCLOGANOIDEI.

_AMIIDÆ._

"Scales cycloid; a long, soft dorsal fin. Abdominal and caudal parts
of the vertebral column subequal in extent." (Günther.)


AMIA.

Body elongate sub-cylindrical, compressed behind; snout short and
rounded. Jaws with an outer series of closely-set pointed teeth, and
with a band of small teeth, similar teeth on the vomer, palatine,
and pterygoid bones. Long dorsal, short anal, and rounded nonfurcate
caudal fin. Ventrals well developed. A single large gular plate;
branchiostegal rays ten to twelve.


Amia (Protamia) uintaensis, Leidy.

Cont. to Ext. Vert. Fauna, p. 185.

A species of large mud-fishes related to the modern _Amia calva_. The
vertebræ are all much wider than they are high. The articular cones
have their bottoms considerably above the centre, and are minutely
perforate for the notochord. The centrum is transversely curved
from side to side, and has the convexity directed forwards; it is
truncate below, making the infero-lateral angles quite prominent in
the anterior dorsal region; in the posterior there are two fossæ.
The diapophyses are large, but almost sessile, and take their origin
above the centre, on the same line as the bottom of the articular
cone. The facets for the neurapophyses are in the form of the figure
8; their internal borders are prominent. The atlas has a broad oval
centrum, which is not truncate below, and has no markings of any
kind on the under surface. The articular faces for the neurapophyses
are prominent, and approach near together. The depression for the
occipital condyle is small, circular, and situated above the centre.

From Henry's Fork.


_Amia depressa_ (?), Marsh.

Pr. Ac. Nat. Sc. 1871, p. 103

In this species the dorsal centra are wide, low, and short, and of a
regular oval outline. The articular cones are shallow, and have their
bottoms but slightly above the centre. The neurapophysial facets are
deep, with prominent borders, and the diapophyses are sessile. The
chief peculiarity is that the under surface of the centrum has no
markings of any kind.

_Measurements._

                                                            M.
  Length of centrum                                        ·010
  Breadth of centrum                                       ·040
  Depth of centrum                                         ·027

As Professor Marsh has given no measurements, the reference to _A.
depressa_ cannot be certain.

The specimen was found at Henry's Fork.


Amia scutata, Cope.

Bull, of U. S. Geol. Survey, No. 1 of Series II, p

A species of about the size of _A. calva_, but with a proportionately
larger head. It is represented in our collection by a specimen
which lacks only a portion of the caudal and pectoral fins. The
_premaxillary_ is short and stout, articulates closely with the
maxillary, and bears a single row of pointed recurved teeth. These
are shorter and straighter than in _A. calva_. The _maxillary_ is
much as in the modern species, but is rounder. The cranio-facial axis
is straight and broad; the _basioccipital_ is the largest of the
bones; the _basisphenoid_ and _presphenoid_ are of the usual shape
and size, but there is a constriction at their junction which is not
marked in the modern species. The _vomer_ is long and double, and at
the extremity is armed with rows of small teeth. The two portions
diverge more perceptibly than in _A. calva_, and are stouter, though
this appearance may, to some extent, be due to flattening.

The _frontal_ is long, broad, and thick; the upper surface is
delicately sculptured in a somewhat different pattern from that seen
in the modern species. The _parietal_ is short and broad, while the
_epiotic_ is unusually narrow. The _mandible_ is long and slender;
the rami are incurved anteriorly, but apparently not to the same
extent as in _A. calva_. The articular has the shape of a long and
narrow wedge; it does not form a very close articulation with the
dentary. The dentary is long and comparatively slender, has a rounded
outline, and is occupied by an external row of large, and an internal
band of small teeth. The mandibular teeth, like those of the upper
jaw, are somewhat different from the teeth of _A. calva_; they are
shorter, stouter, and are not so much incurved or recurved. They
are very sharp, and show a constriction below the apex. The small
teeth are of the usual size and shape. The jugular plate is well
developed, and is long and narrow. The _hyoid arch_ is very much the
same as that shown in the recent species; the characteristic flat
branchiostegals are well marked; they appear to be thirteen in number.

The _scapular arch_ is long and stout. The _clavicle_ is strongly
bent, the supra-clavicle is short, and the _post-clavicle_ is long.
The pectoral fin is too indistinct for description.

The _vertebræ_ are of considerable depth in the anterior dorsal
region, and decrease steadily in size as they go backwards. The
neural spines are long and slender, and project strongly backwards.
The relation of the centra to the arches seems to be about that
seen in _A. calva_, but the neurapophyses are more slender. The
diapophyses are long and slender, in this respect differing from
the Bridger species and approaching the modern one. The dorsals are
thirty-five in number. The caudals number about forty-seven. They
have smaller centra, but longer and stronger neurapophyses than the
dorsals. The hæmal arch is long, and the hæmapophyses articulate
movably with the centra. The spines supporting the caudal fin rays
are very stout. The dorsal fin is long and soft, and has long
interneurals supporting short rays; these are fifty-three in number.
The anal fin, on the other hand, is very short, having but nine rays,
which are long and jointed, and articulate with short interhæmals.
The caudal fin appears to be of the usual form. The _femur_ is of the
general shape characteristic of _Amia_, but is not just like that of
_A. calva_. It is shorter, broader at the proximal end, while the
distal end is narrower, and has a deeper constriction just above it.
The ventral fins are placed under the middle of the dorsal region,
and have each ten rays. The scales are of the usual cycloidal shape,
and minutely striate.

_Measurements._

                                                            M.
  Total length (estimated in part)                         ·404
  Length of head                                           ·093
  Length of vertebral column                               ·253
  Length of caudal fin (estimated)                         ·058
  Length of mandible                                       ·059
  Length of jugular plate                                  ·032
  Length of dorsal region                                  ·141
  Length of caudal region                                  ·112
  Depth of body at origin of dorsal fin
  Length of dorsal fin                                     ·117
  Length of femur                                          ·027

From the insect beds near Florissant, Col.


PAPPICHTHYS, Cope.

U. S. Geol. Survey of the Terrs., 1872, p. 634.

Vertebræ short, dorsal with projecting diapophyses. Maxillary and
dentary bones support but one series of teeth.


Pappichthys plicatus, Cope.

Loc. cit., p. 635.

From Henry's Fork.

Pappichthys lævis, Cope.

Loc. cit., p. 366.

Represented by three vertebræ from the posterior part of the dorsal
region. The centra are subcircular and have deep articular cones,
with their bottoms above the centre, and minutely perforate for
the notochord. The centra are comparatively quite long, and have
prominent projecting rims, and are truncate beneath. The facets for
the neurapophyses are long, and are separated into two parts for the
contiguous arches. The diapophyses are short and stout.

Measurements.

                                                            M.
  Length of centrum                                        ·015
  Breadth of centrum                                       ·0315
  Depth of centrum                                         ·027

Found at Henry's Fork.


Pappichthys symphysis, Cope.

Loc. cit., p. 636.

Found at Cottonwood Creek.


ELASMOBRANCHII.

PLAGIOSTOMATA.

_CARCHARIDÆ._

"Eye with a nictitating membrane. An anal fin; two dorsals."


GALEOCERDO.

Caudal fin with a double notch; mouth crescent shaped; teeth subequal
in both jaws, oblique, serrate on both margins.


Galeocerdo falcatus, Ag.

_Corax falcatus_, Poiss. Foss., t. iii., p. 226.

This species is represented by a single tooth from the cretaceous
sandstone near the Garden of the Gods, Col. It does not agree
exactly with any descriptions or plates which we have seen; but
the differences are probably owing to the position or age of the
specimen. The crown is low, broad, and not very acute, the edge is
finely serrate, and there is no sensible difference between the
serrations of the two borders. The anterior border is undulating in
outline, but for the most part is convex; the posterior is short and
straight, and sends out quite a long heel. One face of the crown is
flat and the other is strongly convex. The root is stout and divided
into two fangs, which are longer and more distinct than is common in
this species. There are no denticles; cementum smooth.

_Measurements._

                                                            M.
  Length of crown                                          ·017
  Depth of fang                                            ·009
  Height of crown                                          ·011


Galeocerdo hartwellii, Cope.

Cret. Vert, p.. 244.

This species belongs to the group _G. Egertonii_, Ag., having the two
edges subequal and symmetrical. A single tooth from Cement Gulch,
Col.


_CESTRACIONTIDÆ._

"Two dorsal fins, an anal; nasal and buccal cavities confluent. Teeth
obtuse, several series being in function." (Günther.)


Ptychodus, Ag.

Poissons Fossiles, t. iii., p. 56.

Ptychodus Whippleyi, Marcou.

Geology of North America, 1858, p. 33.

Represented by a tooth from the cretaceous of Cement Gulch, almost
identical with the specimen described by Dr. Leidy from the
cretaceous of Texas. (Cont. to Ext. Vert. Fauna, p. 300.)




SUMMARY.


  MAMMALIA.

  Primates                 4
  Carnivora                2
  Perissodactyla          16
  Artiodactyla (?)         1
  Amblypoda                3
  Rodentia                 1
                          --   27

  AVES.

  Incertæ sedis            4
                          --    4

  REPTILIA.

  Crocodilia               6
  Chelonia                 5
                          --   11

  PISCES.

  Teleocephali             3
  Nematognathi             1
  Cycloganoidei            6
  Plagiostomata            3
  Incertæ sedis            1
                          --   14
                               --
           Total               56


EXPLANATION OF PLATE A.

_Figure about one fourth natural size._

Uintatherium Leidianum.

[Illustration]


EXPLANATION OF PLATE I.

_Figure three fourths natural size._

Palæosyops paludosus.

Posterior view of cranium.

[Illustration]

EXPLANATION OF PLATE II.

_Figures one fourth natural size._

Palæosyops major.

  Fig. 1.--Axis, view of right side.

  Fig. 2.--Axis, anterior view.

  Fig. 3.--Atlas, posterior view.

  Fig. 4.--Atlas, anterior view.

  Figs. 5 and 6.--Seventh cervical anterior and posterior view.

  Figs. 7 and 8.--Anterior and posterior views of right tibia.

  Figs. 9 and 10.--Proximal and distal faces of same.

  Fig. 11.--Proximal end of fibula.

  Fig. 12.--Right femur, posterior view.

  Fig. 13.--Trochlea of the same.

[Illustration]

EXPLANATION OF PLATE III.

_Figures one half natural size._

Palæosyops paludosus.

  Figs. 1 and 2.--Ulna, anterior view, and distal articular face of same.

  Figs. 3, 4, and 5.--Radius, anterior view; and distal and proximal faces of
          same.

  Fig. 6.--Left scapula.

  Fig. 7.--Right humerus, proximal end, anterior view.

  Fig. 9.--Left manus, anterior view.

Palæosyops major.

  Fig. 8.--Left humerus, anterior view.

[Illustration]

EXPLANATION OF PLATE IV.

_Figure one half natural size._

Leurocephalus cultridens.

Upper and lower jaws. View of right side. Dotted outlines indicate
probable position of lower incisor and canine series.

[Illustration]

EXPLANATION OF PLATE V.

_Figure one half natural size._

Palæosyops major.

Right innominate bone. The iliac crest and position of pubis
estimated in outline.

[Illustration]

EXPLANATION OF PLATE VI.

_Figures one third natural size._

Uintatherium leidianum.

  Fig. 1.--Cervical vertebra, fifth or sixth, anterior view.

  Fig. 2.--Dorsal vertebra, anterior region, view of left side.

  Fig. 3.--Dorsal vertebra, middle region, posterior view.

  Fig. 4.--Last lumbar vertebra, view of right side.

  Fig. 5.--Last lumbar vertebra, posterior view.

  Fig. 6.--Caudal series, first four vertebræ.

[Illustration]

EXPLANATION OF PLATE VII.

_Figures one third natural size._

Uintatherium leidianum.

  Fig. 1.--Anterior view of right humerus.

  Fig. 2.--Ulna, side view, length estimated.

[Illustration]

EXPLANATION OF PLATE VIII.

_Figures one third natural size._

Uintatherium leidianum.


  Fig. 1.---Right scapula. The dotted outline gives an attempted restoration
  of the original shape.

  Fig. 2.--Tibia of left side, anterior view.

  Fig. 3.--View of the proximal articular faces of same.

  Fig. 4.--Right femur, posterior view.

[Illustration]

EXPLANATION OF PLATE IX.

_Figures four fifths natural size._

Orohippus major.

  Fig. 1.--Right femur, anterior view, length estimated.

  Fig. 2.--Right fibula.

  Fig. 3.--Right tibia, anterior view.

  Fig. 4.--Calcaneum.

  Figs. 5 and 6.--Astragalus and navicular.

  Fig. 7.--Metatarsals and phalanges.

  Last Fig.--A carnivorous sacrum, probably belonging to the brain,
  described on pp. 20-22.

[Illustration]

EXPLANATION OF PLATE X.

_Figures 1, 2, 3, 4, and 6, natural size._

Ithygrammodon cameloides.

  Fig. 1.--Left premaxillary, inner view.

  Fig. 2.--Left premaxillary, outer view.

  Fig. 3.--Right maxillary and premaxillary, outer view, premolar, with dotted
  outline indicating its probable position.

  Fig. 4.--The premaxillaries in position (probable), view from above, showing
  size and position of the incisors. Dotted lines indicate the premaxillary
  spine (estimated).

Procamelus occidentalis, Cope, (See Wheeler's Survey, vol. iv., Plate
LXXVII.)

  Fig. 5.--Part of right maxillary and premaxillary, showing single incisor
  with rudimentary alveolus for a second.

  Protolabis ----? Cope. (See Wheeler's Survey, vol iv., p. 343.)

  Fig. 6.--Right maxillary and premaxillary. (This has never been drawn
  before, and was kindly lent to us for this purpose by Prof. Cope.)

Camelus bactrianus. Modern camel.

  Fig. 7.--Right maxillaries, one half natural size.

[Illustration]




SYSTEMATIC CATALOGUE

OF THE

EOCENE VERTEBRATES OF WYOMING.


Although we have endeavored to make this catalogue as complete
and accurate as possible, we feel that errors and omissions are,
from the nature of the case, unavoidable. The material is so vast
and heterogeneous, and is so much scattered throughout numberless
reports, bulletins, journals, and the like, that its correct
compilation is attended with great difficulties. However, a beginning
is here made which will render subsequent work easier. Owing to the
great number of discoveries which have since been made, Dr. Leidy's
excellent catalogue of 1871 covers now but a very small portion of
the ground.

In this list we have made no attempt to decide disputed questions of
priority and synonymy. Doubtless, many of the genera and species here
given will be found to be synonyms of American or European forms;
but at present these questions cannot be settled. Where synonyms
are given, they are the determinations of the original describer
indicated in subsequent publications



MAMMALIA.



PRIMATES.

  Notharctus, Leidy. Pr. Ac. Nat. Sc., 1870, p. 114; Cont. to Ext.
       Vert. Faun., p. 86; Ann. Rep. U. S. Geol. Survey of Terrs.,
       1871, p. 364. _N. tenebrosus_, Leidy, loc. cit.

  Hyopsodus, Leidy. Pr. Ac. Nat. Sc., 1870, p. 110; U. S. Survey of
       Terrs., 1870, p. 354; do. 1871, p. 362; Cont. to Ext. Vert.
       Faun., p. 75.

_H. paulus_, Leidy, loc. cit.

_H. minusculus_, Leidy. Cont. to Ext. Vert. Faun., p. 81.

_H. gracilis_, Marsh. Am. Journ. of Sci., vol. ii., p. 42.

_H. vicarius_, Cope. Described in U. S. Survey of Terrs., 1872, p.
609, as _Microsyops vicarius_. Wheeler's Survey, vol. iv., pt. ii.,
p. 150.

  Microsyops, Leidy. Pr. Ac. Nat. Sc., 1872, p. 20; U. S. Survey of
       Terrs., 1871, p. 363; Cont. to Ext. Vert. Faun., p. 82.

_M. gracilis_, Leidy, loc. cit. In the "Contributions," Dr. Leidy,
considering _Limnotherium_, Marsh, as a synonym of _Microsyops_, has
called this species _M. elegans_.

  Hipposyus, Leidy. Pr. Ac. Nat. Sc., 1872, p. 37; Cont. to Ext.
       Vert. Faun., p. 90.

_H. formosus_, Leidy, loc. cit.

_H. robustior_, Leidy Cont. to Ext. Vert. Faun., p. 93; _Notharctus
robustior_. U. S. Geol. Survey of Terrs., 1871, p. 364.

  Antiacodon, Marsh. Am. Journ. of Sci., 3d Ser. vol. iv., p. 210.

_A. venustus_, Marsh, loc. cit.

  Bathrodon, Marsh. Am. Journ. of Sci., 3d Ser. vol. iv., p. 211.

_B. typus_, Marsh, loc. cit.

  Lemuravus, Marsh. Am. Journ. of Sci., 3d Ser. vol. ix., p. 239.

_L. distans_, Marsh, loc. cit.

  Limnotherium, Marsh. Am. Journ. of Sci., 3d Ser. vol. ii., p. 43.

_L. tyrannus_, Marsh, loc. cit.

_L. elegans_, Marsh, loc. cit.

_L. affine_, Marsh. Am Journ. of Sci., 3d Ser. vol. iv., p. 207.

  Mesacodon, Marsh. Am. Journ. of Sci., 3d Ser. vol. iv., p. 212.

_M. speciosus_, Marsh, loc. cit.

  Palæacodon, Leidy. Pr. Ac. Nat. Sc., 1872; p. 21. U. S. Geol.
       Survey of Terrs., 1871, p. 356; Cont. to Ext. Vert. Faun., p.
       122.

_P. verus_, Leidy, loc. cit.

_P. vagus_, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 224.

  Telmatolestes, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 206.

_T. crassus_, Marsh, loc. cit.

  Tomitherium, Cope. Pr. Am. Phil. Soc., 1872, p. 470; U. S. Geol.
       Survey of Terrs., 1872, p. 546; Wheeler's Survey, vol. iv., p.
       135, pt. ii.

_T. rostratum_, Cope, loc. cit.; U. S. Survey, 1872, p. 548.

  Anaptomorphus, Cope. Pr. Am. Phil. Soc., 1872, p. 554; U. S. Geol.
       Survey of Terrs., 1872, p. 549.

_A. æmulus_, Cope, loc. cit.

  Oligotomus, Cope. On some Eocene mammals, p. 2; U. S. Geol. Survey
       of Terrs., 1872, p. 607.

_O. cinctus_, Cope, loc. cit.

  Opisthotomus, Cope. Wheeler's Survey, vol. iv., p. 151, pt. ii.

_O. astutus_, loc. cit., p. 152.

  Pantolestes, Cope. Pr. Am. Phil. Soc., 1872, p. 467; Wheeler's
       Survey, v. iv., pt. ii., p. 145.

_P. longicaudus_. Pr. Am. Phil. Soc., 1872, p. 467; _Notharctus
longicaudus_, U. S. Geol. Survey of Terrs., 1872, p. 549.

  Sarcolemur, Cope. Pr. Ac. Nat. Sc., 1875, p. 256; Wheeler's Survey,
       v. iv., pt. ii., p. 147.

_S. pygmæus_, Cope. _Lophiotherium pygmæus_, Pr. Am. Phil. Soc.,
1872, extras July 20; _Antiacodon pygmæus_, U. S. Geol. Survey of
Terrs., 1872, p. 607; _Hyopsodus pygmæus_, Pr. Am. Phil. Soc., 1872,
p. 461.

_S. furcatus_, Cope. _Antiacodon furcatus_. On some Eocene mammals,
p. i.; U. S. Geol. Survey of Terrs., 1872, p. 608.

  Thinolestes, Marsh. Am. Journ. Sc., 3d Ser. vol. iv., p. 205.

_T. anceps_, Marsh, loc. cit.


CARNIVORA.

  Uintacyon, Leidy. Pr. Ac. Nat. Sc., 1872, p. 277; Cont. to Ext.
       Vert. Faun., p. 118.

_U. edax_, Leidy, loc. cit.

_U. vorax_, Leidy, loc. cit. Cont. to Ext. Vert. Faun., p. 120.

  Sinopa, Leidy. Pr. Ac. Nat. Sc., 1871, p. 115; U. S. Geol. Survey
       of Terrs., 1871, p. 355; Cont. to Ext. Vert. Faun., p. 116.

_S. rapax_, Leidy, loc. cit.

_S. eximia_, Leidy. Cont. to Ext. Vert. Faun., p. 118.

  Canis.

_C. montanus_, Marsh. Am. Jour. of Sc., 3d Ser. vol. ii., p. 123.

  Dromocyon, Marsh. Am. Jour. of Sc., 3d Ser. vol. xii., p. 403.

_D. vorax_, Marsh, loc. cit.

  Harpalodon, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 216.

_H. sylvestris_, Marsh, loc cit.

_H. vulpinus_, Marsh, loc. cit., p. 217.

  Limnocyon, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 126.

_L. verus_, Marsh, loc. cit.

_L. riparius_, Marsh, loc. cit., p. 203.

_L. agilis_, Marsh, loc. cit., p. 204.

  Limnofelis, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 202.

_L. ferox_, Marsh, loc. cit.

_L. latidens_, Marsh, loc. cit., p. 203.

  Oreocyon, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 406

_O. latidens_, Marsh, loc. cit.

  Thinocyon, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 204.

_T. velox_, Marsh, loc. cit.

  Viverravus, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 127.

_V. gracilis_, Marsh, loc. cit.

_V. (?) nitidus_, Marsh, loc. cit., p. 205.

  Ziphacodon, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 216.

_Z. rugatus_, Marsh, loc. cit.

  Vulpavus, Marsh. Am. Jour. of Sc., 3d Ser. vol. ii., p. 124.

_V. palustris_, Marsh, loc. cit.

  Miacis, Cope. Pr. Am. Phil. Soc., 1872, p. 470.

_M. parvivorus_, loc. cit.; _Viverravus parvivorus_, U. S. Geol.
Survey of Terrs., 1872, p. 560.

  Mesonyx, Cope. Pr. Am. Phil. Soc., 1872. p. 460; U S. Geol. Survey
       of Terrs., 1872, p. 550.

_M. obtusidens_, Cope, loc. cit. U. S. Survey, p. 552.

  Synoplotherium, Cope. Pr. Am. Phil. Soc., 1872, p. 483; U. S. Geol.
       Survey of Terrs., 1872, p. 554.

_S. lanius_, Cope, loc. cit. U. S. Survey, p. 557.

  Stypolophus, Cope. Pr. Am. Phil. Soc., 1872, p. 466; U. S. Geol.
       Survey of Terrs., 1872, p. 559; Wheeler's Survey, vol. iv., p.
       109.

_S. insectivorus_, Cope. Pr, Phil. Soc., 1872, p. 469; U. S. Survey,
1872, p. 557.

_S. pungens_, Cope, loc. cit., pp. 466, 559

_S. brevicalcaratus_, Cope, loc. cit., pp. 469, 560.

  Megencephalon, gen. nov. This report, p 20.

_M. primævus_, sp. nov. This report, p. 20.


UNGULATA.


PERISSODACTYLA.

  Anchitherium.

_A._ (?)----. This report, p. 23.

  Orohippus, Marsh. Am. Jour. of Sc., vol. iv., p. 207; vol. vii., p.
       247.

_O. pumilus_, Marsh, loc. cit., 3d Ser. vol. iv., p. 207.

_O. agilis_, Marsh, loc. cit., 3d Ser. vol. v., p. 407.

_O. major_, Marsh, loc. cit., vol. 3d Ser. vii., p. 248.

_O. gracilis_, Marsh, loc. cit., 3d Ser. vol. vii., p. 249;
_Anchitherium gracile_ 3d Ser. vol. ii., p. 38.

_O. procyoninus_, Cope. Pr. Am. Phil. Soc., 1872, p. 466; U. S. Geol.
Survey, 1872, p. 606.

  Palæosyops, Leidy. Pr. Ac. Nat. Sc., 1870, p. 113; 1871, pp. 114,
       118, 197, 229; 1872, pp. 168, 241; U. S. Geol. Survey, 1870,
       p. 355; 1871, p. 358; Com. to Ext. Vert. Faun., p. 27; Cope,
       U. S. Geol. Survey of Terrs., 1872, p. 591.

_P. paludosus_, Leidy, loc. cit. Cont. to Ext. Vert. Faun., p. 28.

_P. major_, Leidy. U. S. Geol. Survey of Montana, 1871, p. 359; Pr.
Ac. Nat. Sc., 1872, pp. 168, 241; Cont. to Ext. Vert. Faun., p. 45.

_P. humilis_, Leidy. Pr. Ac. Nat. Sc., 1872, p. 168, 277; Cont. to
Ext. Vert. Faun., p. 58.

_P. junius_, Leidy. Pr. Ac. Nat. Sc., 1872, p. 277; Cont. to Ext.
Vert. Faun., p. 57.

_P. lævidens_, Cope. Pr. Am. Phil. Soc., 1873; U. S. Survey, 1872, p.
591.

_P. vallidens_, Cope. Pr. Am. Phil. Soc., 1872, p. 487; loc. cit., p.
592.

_P. minor_, Marsh. Am. Jour. of Sc., vol. ii., p. 36.

  Limnohyus, Leidy. Pr. Ac. Nat. Sc., 1872, p. 242; Cont. to Ext.
       Vert. Faun., p. 58; Marsh, Am. Jour. of Sc., 1872, 3d Ser.
       vol. iv., p. 124.

_L. laticeps_, Marsh. _Palæosyops laticeps_. Am. Journ. Sc. 3d Ser.
vol. iv., p. 122.

_L. robustus_, Marsh, loc. cit., p. 124, is same as _P. major_, Leidy.

_L. diaconus_, Cope. U. S. Geol. Survey of Terrs., 1872, p. 593.

_L. fontinalis_, Cope, loc. cit., p. 594.

  Telmatherium, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 123.

_T. validum_, Marsh, loc. cit.

  Leurocephalus, gen. nov. This report, p. 42.

_L. cultridens_, sp. nov. This report, p. 42.

  Hyrachyus, Leidy. Pr. Ac. Nat. Sc., 1871, p. 229; 1872, pp. 19,
       163; U. S. Geol. Survey, 1871, p. 360; Cont. to Ext. Vert.
       Faun., p. 60.

_H. agrarius_, Leidy, loc. cit.; _H. agrestis_. U. S. Survey, 1871,
p. 357.

_H. eximius_, Leidy. Pr. Ac. Nat. Sc., 1871, p. 229; 1872, p. 163; U.
S. Geol. Survey of Terrs., 1871, p. 361; Cont. to Ext. Vert. Faun.,
p. 66; Cope, U. S. Geol. Survey of Terrs., 1872, p. 595.

_H. modestus_, Leidy. Pr. Ac. Nat. Sc., 1872, p. 20; U. S. Geol.
Survey of Terrs., 1871, p. 361; Cont. to Ext. Vert. Faun., p. 67;
_Lophiodon modestus_, Pr. Ac. Nat. Sc., 1870. p. 109.

_H. nanus_, Leidy. Pr. Ac. Nat. Sc., 3d Ser. 1872, p. 20; U. S.
Survey, 1871, p. 361; Cont. to Ext. Vert. Faun., p. 67.

_H. princeps_, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 125.

_H. implicatus_, Cope. On Some Eocene Mammals, p. 5; U. S. Survey,
1872, p. 604.

_H. crassidens_, sp. nov. This report, p. 52.

_H. imperialis_, sp. nov. This report, p. 50.

_H. intermedius_, sp. nov. This report, p. 51.

_H. paradoxus_, sp. nov. This report, p. 53.

  Helaletes, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 218.

_H. boöps_, Marsh, loc. cit.

_H. latidens_, sp. nov. This report, p. 54.

  Lophiodon.

  _L bairdianus_, Marsh. Am. Jour. of Sc., 3d Ser. vol. ii., p. 36.

  _L. affinis_, loc. cit., p. 37.

  _L. nanus_, loc. cit.

  _L. pumilus_, loc. cit., p. 38.

  Lophiotherium.

_L. sylvaticum_, Leidy. Pr. Ac. Nat. Sc., 1870, p. 126; Cont. to Ext.
Vert. Faun., p. 69.

_L. Ballardi_, Marsh. Am. Jour. of Sc., 3d Ser. vol. ii., p. 39.

  Orotherium, Marsh. Am: Jour. of Sc., 3d Ser. vol. iv., p. 217.

_O. mintanum_, Marsh, loc. cit.

  Helohyus, Marsh. Am. Journ. of Sc., 3d Ser. vol. iv., p. 207.

_H. plicodon_, Marsh, loc. cit.

  Thinotherium, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 208.

_T. validum_, Marsh, loc. cit.


ARTIODACTYLA.

All the forms described under this head are of uncertain reference.

  Elotherium.

_E. lentum_, Marsh. Am. Jour. of Sc., 3d Ser. vol. ii., p. 39.

  Platygonus.

_P. Ziegleri_, Marsh, loc cit., p. 40.

  Parahyus, Marsh. Am. Jour. of Sc., 3d Ser. vol. xii., 402.

_P. vagus_, Marsh, loc. cit.

  Homacodon, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 126.

_H. vagans_, Marsh, loc. cit.

  Ithygrammodon, gen. nov. This report, p. 56.

_I. cameloides_, sp. nov. This report, p. 57.


AMBLYPODA.

Cope. Wheeler's Survey, vol., iv., pt. ii., p. 179.


DINOCERATA.

Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 344; Ibid. vol. v., pp.
117-122, 293; Ibid. vol. vi., p. 300; Ibid. vol. xi., p. 163.

  Uintatherium, Leidy. Pr. Ac. Nat. Sc., 1872, p. 169; Am. Jour. of
       Sc., 3d Ser. vol. iv., p. 239; Cont. to Ext. Vert. Faun., p.
       96.

_U. robustum_, Leidy, loc. cit.; _Uintamastix atrox_, loc. cit.

_U. Leidianum_, sp. nov. This report, p. 3.

_U. princeps_, sp. nov. This report, p. 81.

  Tinoceras, Marsh. _Titanotherium_ (?), Am. Jour. of Sc., 3d Ser.
       vol. ii., p. 35; _Mastodon_, loc. cit., vol. iv., p. 123,
       footnote; _Tinoceras_, loc. cit., vol. iv., pp. 322 and 323.

_T. anceps_, Marsh, loc. cit., vol. iv., p. 322.

_T. grandis_, Marsh, loc. cit., p. 323.

  Dinoceras, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 344; Ibid.
       vol. v., pp. 117-122; Ibid. vol. v., p. 408.

_D. mirabilis_, Marsh, loc. cit., vol. iv., p. 344.

_D. lucaris_, Marsh, loc. cit., vol. v., p. 408.

_D. lacustre_, Marsh, loc. cit., vol. iv., p. 344.

  Loxolophodon, Cope. Pr. Am. Phil. Soc., 1872, pp. 580, 488; U. S.
       Survey, 1872, p. 565.

_L. cornutus_, Cope, loc. cit.; U. S. Survey, 1872, p. 568.

  Eobasileus, Cope. Pr. Am. Phil. Soc., 1872, p. 485; U. S. Survey,
       1872, p. 575.

_E. pressicornis_, Cope. Pr. Am. Phil. Soc., 1872, p. 580; loc. cit.

_E. furcatus_, Cope. U. S. Survey, 1872, p. 580; _Loxolophodon
furcatus_, Pr. Am. Phil. Soc., 1872, p. 580.

  Coryphodon.

_C. hamatus_, Marsh. Am. Jour. of Sc., 3d Ser. vol. xi., p. 425.

  Bathmodon, Cope. Pr. Am. Phil. Soc., 1872, p. 417; U. S. Geol.
       Survey, 1871, p. 350; 1872, p. 586.

_B. radians_, Cope, loc. cit.

_B. semicinctus_, Cope, loc. cit.

_B. latipes_, Cope, loc. cit.

  Metalophodon, Cope. Pr. Am. Phil. Soc., 1872, p. 542; U. S. Geol.
       Survey, 1872, p. 589.

_M. armatus_, Cope, loc. cit.


TILLODONTIA.

Marsh. Am. Jour. of Sc., 3d Ser. vol. ix., p. 221; vol. xi., p. 249.

  Anchippodus, Leidy. Pr. Ac. Nat. Soc., 1868, p. 232; Ext. Mam. N.
       Am., p. 403.

_Trogosus._ Pr. Ac, 1871, p. 113; Cont. to Ext. Vert. Faun., p. 71.

_A. riparius_, Leidy. Pr. Ac. Nat. Soc., 1868, p. 232; Cont. to Ext.
Vert. Faun., p. 71 (as _Trogosus castoridens_).

_A. vetulus_, Leidy; _Trogosus vetulus_, Pr. Ac. Nat. Sc., 1871, p.
229; Cont. to Ext. Vert. Faun., p. 75.

  Tillotherium. Am. Jour. of Sc., 3d Ser. vol. v., p. 485; Ibid. vol.
       xi., p. 249.

_T. hydracoides_, Marsh, loc. cit.

_T. latidens_, Marsh, loc. cit., vol. vii., p. 533.

_T. fodiens_, Marsh, loc. cit., vol. ix., p. 241.

  Stylinodon, Marsh. Am. Jour. of Sc., 3d Ser. vol. vii., p. 532.

_S. mirus_, loc. cit.


RODENTIA.

  Paramys, Leidy. Pr. Ac. Nat. Sc., 1871, p. 231; U. S. Geol. Survey,
       1871, p. 357; Cont. to Ext. Vert. Faun., p. 110.

_P. delicatus_, Leidy, loc. cit.

_P. delicatior_, Leidy, loc. cit.

_P. delicatissimus_, Leidy, loc. cit.; Cont. to Ext. Vert. Faun., p.
111.

_P. robustus_, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 218.

_P. superbus_, sp. nov. This report, p. 84.

_P. leptodus_, Cope. U. S. Geol. Survey, 1872, p. 609.

  Mysops, Leidy. Pr. Ac. Nat. Sc., 1871, p. 232; U. S. Geol. Survey,
       1871, p. 357; Cont. to Ext. Vert. Faun., p. 111.

_M. minimus_, Leidy, loc. cit.

_M. fraternus_, Leidy. Cont. to Ext. Vert. Faun., p. 112.

  Pseudotomus, Cope. Pr. Am. Phil. Soc., 1872, p. 467; U. S. Geol.
       Survey, 1872, p. 610.

_P. hians_, Cope, loc. cit.

  Arctomys, Marsh. Am. Jour. of Sc., 3d Ser. vol. ii., p. 121.

_A. vetus_, Marsh, loc. cit.

  Geomys, Marsh. Am. Jour. of Sc., 3d Ser. vol. ii., p. 121.

_G. bisulcatus_, Marsh, loc. cit.

  Sciuravus, Marsh. Am. Jour. of Sc., 3d Ser. vol. ii., p. 122.

_S. nitidus_, Marsh, loc. cit.

_S. undans_, Marsh, loc. cit.

_S. parvidens_, Marsh, loc. cit., 3d Ser. vol. iv., p. 220.

  Tillomys, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 219.

_T. senex_, Marsh, loc. cit.

_T. parvus_, Marsh, loc. cit.

  Tachymys, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 219.

_T. lucaris_, Marsh, loc. cit.

  Colonymys, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 220.

_C. celer_, Marsh, loc. cit.


INSECTIVORA.

  Omomys, Leidy. Pr. Ac. Nat. Sc., 1869, p. 63; Ext. Mam. of N. Am.,
       p. 408; Cont. to Ext. Vert. Faun., p. 120.

_O. Carteri_, Leidy, loc. cit.

  Washakius, Leidy. Cont. to. Ext. Vert. Faun., p. 123.

_W. insignis_, Leidy, loc. cit.

  Passalacodon, Marsh. Am. Jour. of Sc., vol. iv. p. 208.

_P. litoralis_, Marsh, loc. cit.

  Anisacodon,[4] Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 209.

[Footnote 4: Professor Marsh has subsequently used this name to
designate a genus of the _Brontotheridæ_. Am. Jour. of Sc., vol. ix.,
p. 246.]

_A. elegans_, Marsh, loc. cit.

  Centetodon, Marsh, Am. Jour. of Sc., 3d Ser. vol. iv., p. 209.

_C. pulcher_, Marsh, loc. cit.

_C. altidens_, Marsh, loc. cit., p. 214.

  Hemiacodon, Marsh, Am. Jour. of Sc., 3d Ser. vol. iv., p. 212.

_H. gracilis_, Marsh, loc. cit.

_H. nanus_, Marsh, loc. cit., p. 113

_H. pucillus_, Marsh, loc. cit.

  Entomodon, Marsh, Am. Jour. of Sc., 3d Ser. vol. iv., p. 214.

_E. comptus_, Marsh, loc. cit.

  Entomacodon, Marsh, Am. Jour. of Sc., 3d Ser. vol. iv., p. 214.

_E. minutus_, Marsh, loc. cit.

_E. angustidens_, Marsh, loc. cit., p. 222.

  Apatemys, Marsh, Am. Journ. of Sc., 3d Ser. vol. iv., p. 221.

_A. bellus_, Marsh, loc. cit.

_A. bellulus_, Marsh, loc. cit.

  Talpavus, Marsh, Am. Journ. of Sc., 3d Ser. vol. iv., p. 128.

_T. nitidus_, Marsh, loc cit.


CHIROPTERA.

  Nyctitherium, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 127.

_N. velox_, Marsh, loc. cit.

_N. priscum_, Marsh, loc. cit., p. 128.

  Nyctilestes, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 215.

_N. serotinus_, Marsh, loc. cit.


MARSUPIALIA.

  Triacodon, Marsh. Am. Jour. of Sc., 3d Ser. vol. ii., p. 123.

_T. fallax_, Marsh, loc. cit.

_T. grandis_, Marsh, loc. cit. 3d Ser. vol. iv., p. 222.

_T. nanus_, Marsh, loc. cit., p. 223.

_T. aculeatus_, Cope. Pr. Phil. Soc., 1872, p. 460; U. S. Geol. of
Terrs., 1872, p. 611.


_Genera incertæ sedis._

  Stenacodon, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 210.

_S. rarus_, Marsh, loc. cit.




AVES.


RAPTORES.

  Bubo.

_B. leptosteus_, Marsh. Am. Jour. of Sc., 3d Ser. vol. ii, p. 126.


GRALLATORES.

  Aletornis, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 256.

_A. nobilis_, Marsh, loc. cit.

_A. pernix_, Marsh, loc. cit.

_A. venustus_, Marsh, loc. cit., p. 257.

_A. gracilis_, Marsh, loc. cit., p. 258.

_A. bellus_, Marsh, loc. cit.


SCANSORES.

  Uintornis, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 259.

_U. lucaris_, Marsh, loc. cit.




REPTILIA.


CROCODILIA.

  Crocodilus.

_C. liodon_, Marsh. Am. Jour. of Sc., 3d Ser. vol. i., p. 454.

_C. affinis_, Marsh, loc. cit.

_C. Grinnelli_, Marsh, loc. cit., p. 455.

_C. brevicollis_, Marsh, loc. cit., p. 456.

_C. parvus_, sp. nov. This report, p. 91.

_C. clavis_, Cope. Pr. Am. Phil. Soc., 1872, p. 485; U. S. Geol.
Survey, 1872, p. 612.

_C. sulciferus_, Cope. Pr. Am. Phil. Soc., 1872, p. 555; U. S.
Survey, loc. cit.

_C. hetorodon_, Cope. _Alligator heterodon_, Pr Am. Phil. Soc., 1872,
p. 544; U. S. Geol. Survey, 1872, p. 614.

_C. aptus_, Leidy. Cont. to Ext. Vert. Faun., p. 126.

_C. Elliotii_, Leidy, loc cit.

  Diplocynodus.

_D. subulatus_, Cope. U. S. Geol. Survey, 1872, p. 613; _Crocodilus
subulatus_, Pr. Am. Phil. Soc., 1872, p. 554.

_D. polyodon_, Cope. U. S. Geol. Survey, 1872, p. 614. (In his report
to Lt. Wheeler, Prof. Cope says that "a single species, the _D.
subulatus_, occurs" in the Bridger Basin, (p. 60). It is therefore
probable that he has changed the _D. polyodon_, but we cannot find
its synonym.)


LACERTILIA.

  Saniva, Leidy. Pr. Ac. Nat. Sc., 1870, p. 124; U. S. Survey, 1870,
       p. 368; do., 1871, p. 370; Com. to Ext. Vert. Faun., p. 181.

_S. ensidens_, Leidy, loc. cit.

_S. major_, Leidy. Cont. to Ext. Vert. Faun., p. 182.

  Chameleo.

_C. pristinus_, Leidy. Pr. Ac. Nat. Sc., 1872, p. 277; Cont. to Ext.
Vert. Faun., p. 184.

  Naocephalus, Cope. Pr. Am. Phil. Soc., 1872, p. 465; U. S. Geol.
       Survey, 1872, p. 631.

_N. porrectus_, Cope, loc. cit.; U. S. Geol. Survey, 1872, p. 632.

  Glyptosaurus, Marsh. Pr. Ac. Nat. Sc., 1871, p. 105; Am. Jour. of
       Sc., 3d Ser. vol. i., p. 456.

_G. sylvestris_, Marsh, loc. cit.

_G. nodosus_, Marsh, Am. Jour. of Sc., vol. i., p. 458.

_G. ocellatus_, Marsh, loc. cit., vol. i., p. 458, and vol. iv., p.
306.

_G. anceps_, Marsh, loc. cit., vol. i., p. 458.

_G. princeps_, Marsh, loc. cit., 3d Ser. vol. iv., p. 302.

_G. brevidens_, Marsh, loc. cit., p. 305.

_G. rugosus_, Marsh, loc. cit.

_G. sphenodon_, Marsh, loc. cit., p. 306.

  Thinosaurus, Marsh. Am. Jour. of Sc., 3 Ser. vol. iv., p. 299.

_T. paucidens_, Marsh, loc. cit.

_T. leptodus_, Marsh, loc. cit., p. 300.

_T. crassus_, Marsh, loc. cit., p. 301.

_T. grandis_, Marsh, loc. cit.

_T. agilis_, Marsh, loc. cit., p. 302.

  Oreosaurus, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 303.

_O. vagans_, Marsh, loc. cit.

_O. lentus_, Marsh, loc. cit., p. 307.

_O. gracilis_, Marsh, loc. cit.

_O. microdus_, Marsh, loc. cit., p. 308.

_O. minutus_, Marsh, loc. cit.

  Tinosaurus, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 304.

_T. stenodon_, Marsh, loc. cit.

_T. lepidus_, Marsh, loc. cit., p. 308.

  Iguanavus, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 309.

_I. exilis_, Marsh, loc. cit.

  Limnosaurus, Marsh. Am. Jour. of Sc., 3d Ser. vol. iv., p. 309.

_L. ziphodon_, Marsh, loc. cit.; _Crocodilus ziphodon_, loc. cit.,
vol. i., p. 453.


OPHIDIA.

  Boavus, Marsh. Am. Jour. of Sc., 3d Ser. vol. i., p. 323.

_B. occidentalis_, Marsh, loc. cit.

_B. agilis_, Marsh, loc. cit., p. 324.

_B. brevis_, Marsh, loc. cit.

  Lithophis, Marsh. Am. Jour. of Sc., 3d Ser. vol. i., p. 325.

_L. Sargenti_, Marsh, loc. cit.

  Limnophis, Marsh. Am. Jour. of Sc., 3d Ser. vol. i., p. 326.

_L. crassus_, Marsh, loc. cit.

  Protagras, Cope. Pr. Am. Phil. Soc., 1872, p. 471: U. S. Geol.
       Survey, 1872, p. 632.

_P. lacustris_, Cope, loc. cit.


CHELONIA.

  Testudo.

_T. Corsoni_, Leidy. Pr. Ac. Nat. Sc., 1871, p. 154; 1872, p. 268;
U. S. Geol. Survey, 1871, p. 366; Cont. to Ext. Vert. Faun., p. 132;
_Emys Carteri_, Pr. Ac. Nat. Sc., 1871, p. 228; U. S. Geol. Survey,
1871, p. 367. (Professor Cope refers this species to his _Hadrianus_.)

  Hadrianus, Cope. Pr. Am. Phil. Soc., 1872, p. 468; U. S. Geol.
       Survey of Terrs., 1872, p. 630.

_H. allabiatus_, Cope. Pr. Am. Phil. Soc., 1872, p. 471; U. S.
Survey, loc. cit.

_H. octonarius_, Cope, loc. cit. Pr. Am. Phil. Soc. 1872, p. 468.

EMYS.

_E. wyomingensis_, Leidy. Pr. Ac. Nat. Sc., 1869, p. 66; U. S.
Geol. Survey, 1871, p. 367; Cont. to Ext. Vert. Faun., p. 140. _E.
Feansii_, Pr. Ac. Nat. Sc., 1870, p. 123; _E. stevensoniansis_, loc.
cit., p. 5. _E. Haydem_, loc. cit., p. 123.

_E. septarius_, Cope. U. S. Geol. Survey, 1872, p. 625.

_E. latilabiatus_, Cope. Pr. Am. Phil. Soc., 1872, p. 471; loc. cit.,
p. 626.

_E. gravis_, Cope. _Notomorpha gravis_ and _N. Garmanii_, Pr. Am.
Phil. Soc., 1872, pp. 476-77; _E. gravis_, U. S. Survey, 1872, p. 626.

_E. testudineus_, Cope. U. S. Geol. Survey, 1872, p. 627; _Notomorpha
testudineus_, Pr. Am. Phil. Soc., 1872, p. 475.

_E. euthnætus_, Cope. U. S. Geol. Survey, 1872, p. 628.

_E. megaulax_, Cope, loc. cit.

_E. pachylomus_, Cope, loc. cit., p. 629.

_E. terrestris_, Cope, loc. cit.; _Palæotheca terrestris_, Pr. Am.
Phil. Soc., 1872, p. 464.

_E. polycyphus_, Cope, loc. cit., 630; _P. polycyphus_, loc. cit., p.
463.

  Hybemys, Leidy. Pr. Ac. Nat. Sc., 1871; p. 103; Cont. to Ext. Vert.
       Faun., p. 174.

_H. arenarius_, Leidy, loc. cit.

  Baptemys, Leidy. Pr. Ac. Nat. Sc., 1870, p. 4; U. S. Survey, 1870,
       p. 367; do., 1872, p. 367; Cont. to Ext. Vert. Faun., 157.
       (Professor Cope refers this genus to _Dermatemys Gray_).

_B. wyomingensis_, Leidy, loc. cit.

  Chisternon, Leidy. Pr. Ac. Nat. Sc., 1872, p. 162.

_C. undatum._ Cont. to Ext. Vert. Faun., p. 341; _Baena undata_, Pr.
Ac. Nat. Sc., 1871, p. 228; U. S. Survey, 1871, p. 369; Cont. to Ext.
Vert. Faun., p. 161.

  Baena, Leidy. Pr. Ac. Nat. Sc., 1871, p. 228; U. S. Survey, 1870,
       p. 367; do., 1871, p. 368; Cont. to Ext. Vert. Faun., p. 161.

_B. arenosa_, Leidy, loc. cit.; _Baena affinis_, U. S. Survey, 1870,
p. 367.

_B. hebraica_, Cope. Pr. Am. Phil. Soc., 1872, p. 463; U. S. Survey,
1872, p. 621.

_B. ponderosa_, Cope. U. S. Survey, 1872, p. 624.

  Anosteira, Leidy. Pr. Ac. Nat. Sc., 1871, p. 102, 114; U. S.
       Survey, 1871, p. 370; Cont. to Ext. Vert. Faun., p. 174.

_A. ornata_, Leidy, loc. cit.

_A. radulina_, Cope. Pr. Am. Phil. Soc., 1872, p. 555; U. S. Survey,
1872, p. 650.

  Trionyx.

_T. guttatus_, Leidy. Pr. Ac. Nat. Sc., 1869, p. 66; 1870, p. 5;
1871, p. 228; U. S. Geol. Survey, 1870, p. 367; do., 1871. p. 370;
Cont. to Ext. Vert. Faun., p. 176.

_T. uintaensis_, Leidy. Pr. Ac. Nat. Sc., 1872, p. 267; Cont. to Ext.
Vert. Faun., p. 178.

_T. heteroglyptus_, Cope. U. S. Geol, Survey, 1872, p. 616.

_T. scutumantiquum_, Cope, loc. cit., p. 617.

_T. concentricus_, Cope, loc. cit.; Pr. Am. Phil. Soc., 1872, p. 469.

  Axestus, Cope. Pr. Am. Phil. Sc., 1872, p. 462; U. S. Geol. Survey,
       1872, p. 615.

_A. byssinus_, Cope, loc. cit., p. 616.

  Plastomenus, Cope. U. S. Geol. Survey of Terrs. 1872, p. 617.

_P. Thomasii_, Cope, loc. cit., p. 618; _Trionyx Thomasii_, Pr. Am.
Phil. Soc., 1872, p. 462.

_P. trionychoides_, Cope, loc. cit., 619; _Anostira trionychoides_,
Pr. Am. Phil. Soc., 1872, p. 461.

_P. multifoveatus_, Cope, loc. cit., p. 619.

_P. ædemius_, Cope, loc. cit.; _Anostira ædemius_, Pr. Am. Phil.
Soc., 1872, p. 461.

_P. molopinus_, Cope, loc. cit. p. 620; _Anostira molopinus_, Pr. Am.
Phil. Soc., 1872, p. 461.


AMPHIBIA.

Incertæ sedis, I, Cope. U. S. Geol. Survey, 1872, p. 633.




PISCES

TELEOCEPHALI.

  Clupea.

_C. humilis_, Leidy. Pr. Ac. Nat. Sc., 1856, p. 266; U. S. Geol.
Survey, 1870, p. 369; do., 1871, p. 372; Cont. to Ext. Vert. Faun.,
p. 195.

_C. alta_, Leidy. Cont. to Ext. Vert. Faun., p. 196. (Cope refers
these two species to _Diplomystus_ )

_C. pusilla_, Cope. Pr. Am. Phil. Soc., 1870, p. 382; U. S. Survey,
1870, p. 429.

  Diplomystus, Cope. U. S. Geol. Survey Bulletin, vol. iii., No, 4,
       p. 808.

_D. dentatus_, Cope, loc. cit.

_D. analis_, Cope, loc. cit., p. 809.

_D. pectorosus_, Cope, loc. cit., p. 810.

  Osteoglossum.

_O. encaustum_, Cope. U. S. Geol. Survey, 1870, p. 430.

  Dapedoglossus, Cope. U. S. Geol. Survey; Bulletin, vol. iii., No.
       4, p. 807.

_D. testis_, Cope, loc. cit.

_D. æquipinnis_, Cope, loc. cit., vol. iv., No. 1, p. 77.

  Erismatopterus, Cope. U. S. Geol. Survey, 1870, p. 427.

_E. Rickseckeri_, Cope, loc. cit.

_E. levatus_, Cope, loc. cit., p. 428; _Cyprinodon levatus_, Pr. Am.
Phil. Soc., 1870, p. 382.

_E. Endlichi_, Cope. U. S. Geol. Survey Bulletin, vol. iii., No. 4,
p. 811.

  Amphiplaga, Cope. U. S. Geol Survey Bull., vol. iii., No. 4, p. 812.

_A. brachyptera_, Cope, loc. cit.

  Asineops, Cope. Pr. Am. Phil. Soc., 1870, p. 380; U. S. Geol.
       Survey, 1870, p. 425.

_A. squamifrons_, Cope. Pr. Phil. Soc., p. 381; U. S. Survey, 1870,
p. 426.

_A. vividensis_, Cope. U. S. Survey, 1870, p. 426.

_A. pauciradiatus_, Cope. U. S. Geol. Survey Bull., vol. iii., No. 4,
p. 813.

  Mioplosus, Cope. U. S. Geol. Survey Bull., vol. iii., No. 4, p. 813.

_M. abbreviatus_, Cope, loc. cit.

_M. labracoides_, Cope, loc. cit., p. 814.

_M. longus_, Cope, loc. cit., p. 815.

_M. Beanii_, Cope, loc. cit., p. 816.

  Priscacara, Cope. U. S. Geol. Survey Bull., vol. iii., No. 4, p.
       816.

_P. serrata_, Cope, loc. cit.

_P. cypha_, Cope, loc. cit., p. 817.

_P. liops_, Cope, loc. cit., p 818.

_P. oxyprion_, Cope, loc. cit., vol. iv., No. i, p. 74.

_P. Pealeii_, Cope, loc. cit., p. 75.

_P. clivosa_, Cope, loc. cit., p. 76.


NEMATOGNATHI.

  Pimelodus.

_P. antiquus_, Leidy. Pr. Ac. Nat. Sc., 1873, p. 99; Cont. to Ext.
Vert. Faun., p. 193.

  Phareodon, Leidy. Pr. Ac. Nat. Sc., 1873, p. 99; Cont. to Ext.
       Vert. Faun., p. 193.

_P. acutus_, Leidy, loc. cit.

_P. sericeus_, Cope, U. S. Geo!. Survey, 1872, p. 638.

  Rhineastes, Cope. Pr. Am. Phil. Soc., 1872, p. 486; U. S. Geol.
       Survey, 1872, p. 638.

_R. peltatus_, Cope, loc. cit.

_R. Smithii_, Cope, loc. cit.

_R. radulus_, Cope. U. S. Geol. Survey, 1872, p. 639.

_R. calvus_, Cope, loc. cit., p. 640.

_R. arcuatus_, Cope, loc. cit., p. 641.


CYCLOGANOIDEI.

  Amia. _A. (Protamia) uintaensis_, Leidy. Pr. Ac. Nat. Sc., 1873, p.
       98; Cont., p. 185.

_A. (Protamia) media_, Leidy, loc. cit.; Cont. to Ext. Vert. Faun.,
p. 108.

_A. (Protamia) gracilis_, Leidy, loc. cit.

_A. depressa_, Marsh. Pr. Ac Nat. Sc., 1871, p. 105.

_A. Newberriana_, Marsh, loc. cit.

  Hypamia, Leidy. Pr. Ac. Nat. Sc., 1873, p. 98; Cont. to Ext. Vert.
       Faun., p. 189.

_H. elegans_, Leidy, loc. cit.

  Pappichthys, Cope. U. S. Geol. Survey, 1872, p. 634.

_P. sclerops_, Cope, loc. cit., p. 635.

_P. plicatus_, Cope, loc. cit.

_P. lævis_, Cope, loc. cit., p. 636.

_P. symphysis_, Cope, loc. cit.

_P. Corsonii_, Cope, loc. cit.


RHOMBOGANOIDEI.

  Lepidosteus. _L. atrox_, Leidy. Pr. Ac. Nat. Sc., 1873, p. 97;
       Cont. to Ext. Vert. Faun., p. 189.

_L. simplex_, Leidy. Pr. Ac. Nat. Sc., 1873, p. 98; Cont. to Ext.
Vert. Faun , p. 191.

_L. notabilis_, Leidy, loc. cit.

_L. glaber_, Marsh. Pr. Ac. Nat. Sc., 1872, p. 103.

_L. Whitneyi_, Marsh, loc. cit. (These species are all referred to
_Clastes_ by Cope.)

  Clastes, Cope. U. S. Geol. Survey, 1872, p. 633.

_C. anax_, Cope, loc. cit.

_C. cyliferus_, Cope, loc. cit., p. 634.


                  *       *       *       *       *


Transcriber Note

Minor typos were corrected.