MAMMALIA,


                              Described by

                       GEORGE R. WATERHOUSE, ESQ.
         CURATOR OF THE ZOOLOGICAL SOCIETY OF LONDON, ETC. ETC.

                                  WITH

                  A NOTICE OF THEIR HABITS AND RANGES,

                 BY CHARLES DARWIN, ESQ., M.A., F.R.S.
                  SECRETARY TO THE GEOLOGICAL SOCIETY.

              ILLUSTRATED BY NUMEROUS COLOURED ENGRAVINGS.




                                  THE
                                ZOOLOGY
                                   OF
                      THE VOYAGE OF H.M.S. BEAGLE,
              UNDER THE COMMAND OF CAPTAIN FITZROY, R.N.,
                            DURING THE YEARS
                             1832 to 1836.


                    _PUBLISHED WITH THE APPROVAL OF
          THE LORDS COMMISSIONERS OF HER MAJESTY’S TREASURY._


                      Edited and Superintended by
               CHARLES DARWIN, ESQ. M.A. F.R.S. SEC. G.S.
                     NATURALIST TO THE EXPEDITION.


                                PART II.
                               MAMMALIA,
                                   BY
                       GEORGE R. WATERHOUSE, ESQ.
         CURATOR OF THE ZOOLOGICAL SOCIETY OF LONDON, ETC. ETC.


                                LONDON:
            PUBLISHED BY SMITH, ELDER AND CO. 65, CORNHILL.
                              MDCCCXXXIX.




                                LONDON:
                     PRINTED BY STEWART AND MURRAY,
                              OLD BAILEY.




                       GEOGRAPHICAL INTRODUCTION.

                             BY MR. DARWIN.


The object of the present Introduction, is briefly to describe the
principal localities, from which the Zoological specimens, collected
during the voyage of the Beagle, were obtained. At the conclusion of
this work, after each species has been separately examined and
described, it will be more advantageous to incorporate any general
remarks. The Beagle was employed for nearly five years out of England;
of this time a very large proportion was spent in surveying the coasts
of the Southern part of South America, and of the remainder, much was
consumed in making long passages during her circumnavigation of the
globe. Hence nearly the entire collection, especially of the animals
belonging to the higher orders, was procured from this continent; to
which, however, must be added the Galapagos Archipelago, a group of
islands in the Pacific, but not far distant from the American coast. The
localities may be briefly described under the following heads.

BRAZIL. This country presents an enormous area, supporting the most
luxuriant productions of the intertropical regions. It is composed of
primary formations, and may be considered as being hilly rather than
mountainous. LA PLATA includes the several provinces bordering that
great river;—namely, Buenos Ayres, Banda Oriental, Santa Fé, Entre Rios,
&c. My collections were chiefly made at BUENOS AYRES, at MONTE VIDEO,
the capital of Banda Oriental, and at MALDONADO, a town in the same
province, situated on the northern shore, near the mouth of the estuary
of the Plata. These countries consist either of an undulating surface,
clothed with turf, or of perfectly level plains with enormous beds of
thistles. Except on the banks of the rivers, trees nowhere grow; there
are, however, thickets in some of the valleys, in the more hilly parts
of Banda Oriental. During the winter and spring of this hemisphere, a
considerable quantity of rain falls, and the plains of turf are then
everywhere verdant; but in summer the country assumes a brown and
parched appearance.

BAHIA BLANCA forms a large bay, in latitude 39° S. on a part of the
coast, which falls within the territory of the province of Buenos Ayres,
but which from its physical conditions would more properly be classed
with Patagonia. The tertiary plains of PATAGONIA, extend from the Strait
of Magellan to the Rio Negro, which is commonly assumed as their
Northern boundary. This space of more than seven hundred miles in
length, and in breadth reaching from the Cordillera to the Atlantic
Ocean, is everywhere characterised by the dreary uniformity of its
landscape. Nearly desert plains, composed of a thick bed of shingle, and
often strewed over with sea-shells, (plainly indicating that the land
has been covered within a recent period by the sea,) are but rarely
interrupted by hills of porphyry, and other crystalline rocks. The
plains support scattered tufts of wiry grass, and stunted bushes; whilst
in the broad flat-bottomed valleys, dwarf thorn-bearing trees, barely
ornamented with the scantiest foliage, sometimes unite into thickets;
and here the few feathered inhabitants of these sterile regions resort.
There is an extreme scarcity of water; and where it is found, especially
if in lakes, it is generally as salt as brine. The sky in summer is
cloudless, and the heat in consequence, considerable; whereas the frosts
of winter are, sometimes, severe. The principal localities visited by
the Beagle, were the RIO NEGRO, in latitude 41° S., PORT DESIRE, PORT
ST. JULIAN, and SANTA CRUZ. At the latter place, a party, under the
command of Captain FitzRoy, followed up the river in boats, to within a
few miles of the Cordillera; and an opportunity was thus afforded of
verifying the nature of the country in its entire breadth. At the Rio
Negro the plains are much more thickly covered with bushes, (chiefly
acacias,) than in any other part of Patagonia.

TIERRA DEL FUEGO may be supposed to include all the broken land south of
a line joining the opposite mouths of the Strait of Magellan. The land
is mountainous, and may be aptly compared to a lofty chain, partly
submerged in the sea;—bays and channels occupying the position of
valleys. The Eastern side almost exclusively consists of clay-slate; the
Western, of primary, and various plutonic formations. The mountains,
from the water’s edge, to within a short distance of the lower limit of
perpetual snow, are everywhere (excepting on the exposed western shores)
concealed by an impervious forest, the trees of which do not
periodically shed their leaves. On the East coast, the outline of the
land shows that tertiary formations, like those of Patagonia, extend
south of the Strait of Magellan; but with the exception of this part, it
is rare to find even a small space of level ground; and where such
occurs, a thick bed of peat invariably covers the surface. The climate
is of that kind which has been denominated insular: the winters are far
from being excessively cold, whilst the summers are gloomy, boisterous,
and seldom cheered by the rays of the sun. In all seasons, a large
quantity of rain falls. Hence, from the physical conditions of Tierra
del Fuego, all the land animals must live either on the sea-beach, (and
in this class the Aborigines may be included) or within the humid and
entangled forests.

The FALKLAND ISLANDS are situated in the same latitude as the Eastern
entrance of the Strait of Magellan, and about 270 miles East of it. The
climate is nearly the same as in Tierra del Fuego, but the surface of
the land, instead of being as there, concealed by one great forest, does
not support a single tree. We see on every side a withered and coarse
herbage, with a few low bushes, which spring from the peaty soil of an
undulating moorland. Scattered hills, and a central range of quartz
rock, protrude through formations of clay-slate and sand-stone
(belonging to the Silurian epoch,) which compose the lower country.

The structure of the west coast of South America, from the Strait of
Magellan northward to latitude 38°, in its greater part, (as far north
as Chiloe) is very similar to that of Tierra del Fuego. The climate
likewise is similar,—being gloomy, boisterous, and extremely humid; and,
consequently, the land is concealed by an almost impenetrable forest. In
the northern part of this region, the temperature of course is
considerably higher than near the Strait of Magellan; but nevertheless
it is much less so, than might have been anticipated from so great a
change in latitude. Hence, although the vegetation of this northern
district presents a marked difference when compared with that of the
southern; yet the zoology in many respects has, like the general aspect
of the landscape, a very uniform character. The specimens were chiefly
collected from the PENINSULA OF TRES MONTES, the CHONOS ARCHIPELAGO
(from latitude 46° to 43° 30′), CHILOE with the adjoining islets, and
VALDIVIA. The contrast between the physical conditions and productions
of the East and West coasts of this part of South America is very
remarkable. On one side of the Cordillera, great heavy clouds are driven
along by the western gales in unbroken sheets, and the indented land is
clothed with thick forests; whilst on the other side of this great
range, a bright sky, with a clear and dry atmosphere, extends over wide
and desolate plains.

CHILE in the neighbourhood of CONCEPCION (latitude 36° 42′ S.) may be
called a fertile land; for it is diversified with fine woods, pasturage,
and cultivated fields. But towards the more central districts (near
VALPARAISO and SANTIAGO) although by the aid of irrigation, the soil in
the valleys yields a most abundant return, yet the appearance of the
hills, thinly scattered with various kinds of bushes and cylindrical
Opuntias, bespeaks an arid climate. In winter, rain is copious, but
during a long summer of from six to eight months, a shower never
moistens the parched soil. The country has a very alpine character, and
is traversed by several chains of mountains extending parallel to the
Andes. These ranges include between them level basins, which appear once
to have formed the beds of ancient channels and bays, such as those now
intersecting the land further to the south. North of the neighbourhood
of Valparaiso, the climate rapidly becomes more and more arid, and the
land in proportion desert. Beyond the valley of COQUIMBO (latitude 30°.)
it is scarcely habitable, excepting in the valleys of Guasco, Copiapó,
and Paposa, which owe their entire fertility to the system of
irrigation, invented by the aboriginal Indians and followed by the
Spanish colonists. Northward of these places, the absolute desert of
Atacama forms a complete barrier, and eastward, the snow-clad chain of
the Cordillera separates the Zoological province of Chile, from that of
the wide plains which extend on the other side of the Andes.

The last district which it is at all necessary for me to mention here,
is that of the GALAPAGOS ARCHIPELAGO, situated under the Equator, and
between five and six hundred miles West of the coast of America. These
islands are entirely volcanic in their composition; and on two of them
the volcanic forces have within late years been seen in activity. There
are five principal islands, and several smaller ones: they cover a space
of 2° 10′ in latitude, and 2° 35′ in longitude. The climate, for an
equatorial region, is far from being excessively hot: it is extremely
dry; and although the sky is often clouded, rain seldom falls, excepting
during one short season, and then its quantity is variable. Hence, in
the lower part of these islands, even the more ancient streams of lava
(the recent ones still remaining naked and glossy) are clothed only with
thin and nearly leafless bushes. At an elevation of 1200 feet, and
upwards, the land receives the moisture condensed from the clouds, which
are drifted by the trade wind over this part of the ocean at an
inconsiderable height. In consequence of this, the upper and central
part of each island supports a green and thriving vegetation; but from
some cause, not very easily explained, it is much less frequented, than
the lower and rocky districts are, by the feathered inhabitants of this
archipelago.

By a reference to the localities here described, it is hoped that the
reader will obtain some general idea of the nature of the different
countries inhabited by the several animals, which will be described in
the following sheets.

The vertebrate animals in my collection have been presented to the
following museums:—the Mammalia and Birds to the Zoological Society; the
Fishes to the Cambridge Philosophical Society; and the Reptiles, when
described, will be deposited in the British Museum. For the care and
preservation of all these and other specimens, during the long interval
of time between their arrival in this country and my return, I am deeply
indebted to the kindness of the Rev. Professor Henslow of Cambridge.
With respect to the gentlemen, who have undertaken the several
departments of this publication, I hope they will permit me here to
express the great personal obligation which I feel towards them, and
likewise my admiration at the disinterested zeal which has induced them
thus to bestow their time and talents for the good of Science.




                            LIST OF PLATES.


 Plate I. Desmodus D’Orbignyi.

      II. Phyllostoma Grayi.

     III. Vespertilio Chiloensis.

      IV. Canis antarcticus.

       V. —— Magellanicus.

      VI. —— fulvipes.

     VII. —— Azaræ.

    VIII. Felis Yagouaroundi.

      IX. —— Pajeros.

       X. Delphinus Fitz-Royi.

      XI. Mus longicaudatus.

          —— gracilipes.

     XII. —— elegans.

          —— bimaculatus.

    XIII. —— flavescens.

          —— arenicola.

     XIV. —— Magellanicus.

          —— brachiotis.

      XV. —— Renggeri.

          —— obscurus.

     XVI. —— longipilis.

    XVII. —— xanthorhinus.

          —— nasutus.

   XVIII. —— tumidus.

     XIX. —— Braziliensis.

      XX. —— micropus.

     XXI. —— griseo-flavus.

    XXII. —— xanthopygus.

   XXIII. —— Darwinii.

    XXIV. —— Galapagoensis.

     XXV. —— fuscipes.

    XXVI. Reithrodon cuniculoïdes.

   XXVII. —— chinchilloïdes.

  XXVIII. Abrocoma Bennettii.

    XXIX. —— Cuvieri.

     XXX. Didelphis crassicaudata.

    XXXI. —— elegans.

   XXXII. —— brachyura.

  XXXIII. Skulls, and molar teeth of various species of Rodents.

  Fig. 1. _a._ Skull of _Abrocoma Cuvieri_—natural size.

     — 1. _b._ Side view of ditto.

     — 1. _c._ _Ramus_ of lower jaw—outer side.

     — 1. _d._ Lower jaw seen from above.

     — 1. _e._ Molar teeth of the upper jaw magnified.

     — 1. _f._ ditto of lower jaw.

     — 2. _a._ Skull of _Reithrodon cuniculoïdes_.

     — 2. _b._ Incisors of the upper jaw magnified.

     — 2. _c._ Molar teeth of the upper jaw magnified.

     — 2. _d._ ditto of the lower jaw.

     — 2. _e._ ditto of upper jaw of a younger specimen.

     — 3. _a._ Portion of a skull of _Mus Braziliensis_.

     — 3. _b._ ditto, view of palate.

     — 3. _c._ Molar teeth of the upper jaw magnified.

     — 3. _d._ ditto of lower jaw.

     — 4. _a._ Molar teeth of lower jaw of _Reithrodon typicus_
            magnified.

     — 5. _a._ Molar teeth of the upper jaw of _Mus canescens_.

     — 5. _b._ ditto of under jaw.

     — 5. _c._ Skull of ditto.

     — 5. _d._ Posterior molar of the lower jaw more worn than in 5.
            _b._

     — 6. _a._ Molar teeth of the lower jaw of _Mus longipilis_.

     — 6. _b._ Molar teeth of the upper jaw.

     — 7. _a._ Skull of _Mus nasutus_.

     — 7. _b._ Molar teeth of upper jaw.

     — 7. _c._ ditto of lower jaw.

     — 8. _a._ Skull of _Mus Galapagoensis_.

     — 8. _b._ Molar teeth of upper jaw.

     — 8. _c._ ditto of lower jaw.

   XXXIV. Skulls and molar teeth of various species of Rodents, &c.

  Fig. 1. _a._ Skull of _Mus longicaudatus_—natural size.

     — 1. _b._ Molar teeth of upper jaw of ditto.

     — 1. _c._ ditto of lower jaw.

     — 1. _d._ _Ramus_ of lower jaw—natural size.

     — 2. _a._ Skull of _Mus elegans_—natural size.

     — 2. _b._ Molar teeth of upper jaw.

     — 2. _c._ ditto of lower jaw.

     — 3. _a._ Skull of _Mus bimaculatus_—nat. size.

     — 3. _b._ Molar teeth of upper jaw.

     — 3. _c._ ditto of lower jaw.

     — 3. _d._ _Ramus_ of lower jaw—natural size.

     — 4. _a._ Skull of _Mus gracilipes_.

     — 4. _b._ Molar teeth of upper jaw.

     — 4. _c._ ditto of lower jaw.

     — 4. _d._ View of the under side of the tarsus.

     — 5. _a._ First and second molar teeth of upper jaw of _Mus
            flavescens_.

     — 5. _b._ Two posterior molar teeth of the lower jaw of ditto.

     — 6. _a._ Molar teeth of the upper jaw of _Mus Magellanicus_.

     — 6. _b._ ditto of lower jaw.

     — 7. _a._ Skull of _Mus arenicola_.

     — 7. _b._ Molar teeth of upper jaw.

     — 7. _c._ ditto of lower jaw.

     — 7. _d._ _Ramus_ of lower jaw.

     — 8. _a._ Molar teeth of upper jaw of _Mus brachiotis_.

     — 8. _b._ Two posterior molars of lower jaw.

     — 9. _a._ Molar teeth of upper jaw of _Mus obscurus_.

     — 9. _b._ ditto of lower jaw.

    — 10. _a._ _Ramus_ of lower jaw of _Mus nasutus_.

    — 11. _a._ Molar teeth of lower jaw of _Mus tumidus_.

    — 12. _a._ _Ramus_ of lower jaw of _Mus Braziliensis_.

    — 13. _a._ Molar teeth of upper jaw of _Mus micropus_.

    — 13. _b._ ditto of lower jaw.

    — 14. _a._ _Ramus_ of lower jaw of _Mus Galapagoensis_.

    — 15. _a._ Molar teeth of upper jaw of _Mus griseo-flavus_.

    — 15. _b._ ditto of lower.

    — 16. _a._ Molar teeth of upper jaw of _Mus xanthopygus_.

    — 16. _b._ ditto of lower jaw.

    — 17. _a._ Molar teeth of upper jaw of _Mus Darwinii_.

    — 17. _b._ ditto of lower.

    — 18. _a._ Molar teeth of upper jaw of _Mus Gouldii_.

    — 18. _b._ ditto of lower.

    — 19. _a._ Molar teeth of upper jaw of _Mus insularis_.

    — 19. _b._ ditto of lower jaw.

    — 19. _c._ Portion of ramus of lower jaw.

    — 20. _a._ Skull of _Reithrodon chinchilloïdes_—natural size.

    — 20. _b._ ditto, viewed from beneath.

    — 20. _c._ ditto, side view.

    — 20. _d._ _Ramus_ of lower jaw—natural size.

    — 20. _e._ Molar teeth of upper jaw.

    — 20. _f._ ditto of lower.

    — 21. _a._ Skull of _Reithrodon cuniculoïdes_, viewed from beneath.

    — 21. _b._ ditto, side view of fore part.

    — 21. _c._ _Ramus_ of lower pair.

    — 22. _a._ Hinder part of ramus of lower jaw of _Abrocoma
            Bennettii_.

    — 23. _a._ Skull of _Abrocoma Cuvieri_, viewed from beneath.

    — 23. _b._ Lower jaw of ditto, viewed from beneath.

    — 23. _c._ _Ramus_ of lower jaw, inner side.

    — 24. _a._ _Ramus_ of lower jaw of _Octodon Cumingii_, inner side.

    — 25. _a._ Skull of _Didelphis crassicaudata_.

    — 25. _b._ ditto, viewed from beneath.

    — 25. _c._ Side view of fore part of skull.

    — 25. _d._ _Ramus_ of lower jaw, outer side.

    XXXV. Skulls of various animals.

 Fig.  1. _a._ Skull of _Desmodus D’Orbignyi_.

     — 1. _b._ ditto, viewed from beneath.

     — 1. _c._ ditto, side view.

     — 1. _d._ Front view of the incisors, and canines of upper jaw
            magnified.

     — 1. _e._ Side view of do. and the molar teeth.

     — 1. _f._ Front view of incisors and canines of lower jaw,
            magnified.

     — 1. _g._ Side view of ditto, and molar teeth.

     — 2. _a._ Skull of _Phyllostoma Grayi_.

     — 2. _b._ Side view of ditto.

     — 2. _c._ } Front view of incisors of upper and

     — 2. _d._ }   lower jaws magnified.

     — 3. _a._ Skull of _Vespertilio Chiloensis_.

     — 3. _b._ Side view of ditto.

     — 3. _c._ Front view of upper and lower incisors magnified.

     — 4. _a._ Skull of _Lutra Platensis_.

     — 4. _b._ Under view of ditto.

     — 4. _c._ Side view of fore part of ditto.

     — 4. _d._ Upper view of lower jaw of ditto.

     — 5. _a._ Skull of _Didelphis elegans_.

     — 5. _b._ Under view of ditto.[1]

     — 5. _c._ Side view ditto.

     — 5. _d._ _Ramus_ of lower jaw, outer side.

     — 5. _e._ The same, viewed from above, and magnified.




                         INDEX TO THE SPECIES.


                                               Page
                     Abrocoma Bennettii          85
                     —— Cuvieri                  86
                     Auchenia Llama              26
                     Canis antarcticus            7
                     —— Azaræ                    14
                     —— fulvipes                 12
                     —— Magellanicus             10
                     Cavia Cobaia                89
                     —— Patachonica              89
                     Cervus campestris           29
                     Ctenomys Braziliensis       79
                     Dasypus hybridus            92
                     —— minutus                  93
                     Delphinus Fitz-Royi         25
                     Desmodus D’Orbignyi          1
                     Didelphis Azaræ             93
                     —— brachyura                97
                     —— crassicaudata            94
                     —— elegans                  95
                     Dysopes nasutus              6
                     Felis domesticus            20
                     —— Pajeros                  18
                     —— Yagouaroundi             16
                     Gallictis vittata           21
                     Hydrochœrus Capybara        91
                     Kerodon Kingii              88
                     Lagostomus trichodactylus   88
                     Lepus Magellanicus          92
                     Lutra Chilensis             22
                     —— Platensis                21
                     Mus arenicola               48
                     —— bimaculatus              43
                     —— brachiotis               49
                     —— Braziliensis             58
                     Mus canescens               54
                     —— Darwinii                 64
                     —— decumanus                31
                     —— —— var. Maurus           33
                     —— elegans                  41
                     —— flavescens               46
                     —— fuscipes                 66
                     —— Galapagoensis            65
                     —— Gouldii                  67
                     —— gracilipes               45
                     —— griseo-flavus            62
                     —— Jacobiæ                  34
                     —— longicaudatus            39
                     —— longipilis               55
                     —— Magellanicus             47
                     —— micropus                 61
                     —— Musculus                 38
                     —— nasutus                  56
                     —— obscurus                 52
                     —— Rattus var. Insularis    35
                     —— Renggeri                  5
                     —— tumidus                  57
                     —— xanthopygus              63
                     —— xanthorhinus             53
                     Myopotamus Coypus           78
                     Octodon Cumingii            82
                     Phyllostoma Grayi            3
                     —— perspicillatum            4
                     Poephagomys ater            82
                     Reithrodon chinchilloïdes   72
                     —— cuniculoïdes             69
                     —— typicus                  71
                     Vespertilio Chiloensis       5




                                LONDON:
                     PRINTED BY STEWART AND MURRAY,
                              OLD BAILEY.




                               MAMMALIA,


                              Described by

                       GEORGE R. WATERHOUSE, ESQ.
         CURATOR OF THE ZOOLOGICAL SOCIETY OF LONDON, ETC. ETC.

                                  WITH

                  A NOTICE OF THEIR HABITS AND RANGES,

                BY CHARLES DARWIN, ESQ. M.A. F.G.S. &c.
            CORRESPONDING MEMBER OF THE ZOOLOGICAL SOCIETY.




                               MAMMALIA.




                         FAMILY—PHYLLOSTOMIDÆ.


                          DESMODUS D’ORBIGNYI.
      PLATE I. Natural size. Skull, teeth, &c. Pl. XXXV., figs. 1.

  _D. pilis nitidis adpressis; corpore suprà fusco, pilis ad basin
    albis; gulâ abdomineque cinerescenti-albis; nasûs prosthemate
    parvulo bifido._

  DESCRIPTION.—The fur of this Bat is glossy and has a silk-like
      appearance; that on the top of the head, sides of the face, and
      the whole of the upper parts of the body, is of a deep brown
      colour; all the hairs on these parts, however, are white at the
      base. The flanks, interfemoral membrane, and the arms, are also
      covered on their upper side with brown hairs. On the lower part of
      the sides of the face, and the whole of the under parts of the
      body, the hairs are of an ashy-white colour. The membrane of the
      wing is brownish. The ears are of moderate size, and somewhat
      pointed; externally they are covered with minute brown hairs, and
      internally with white. The tragus is also covered with white
      hairs; it is of a narrow form, pointed at the tip, and has a small
      acute process in the middle of the outer margin. The nose-leaf is
      pierced by the nostrils, which diverge posteriorly, and is so
      deeply cleft on its hinder margin, that it may be compared to two
      small leaflets joined side by side near their bases. These
      leaflets, unlike the nose-leaf of the Phyllostomina, lie
      horizontally on the nose to which they are attached throughout, a
      slight ridge only indicating their margin. Around the posterior
      part of the nose-leaf there is a considerable naked space, in
      which two small hollows are observable, situated one on each side,
      and close to the nose-leaf; and, at a short distance behind the
      nose-leaf, this naked membrane is slightly elevated, and forms a
      transverse fleshy tubercle.

                                                              In. Lines.
 Length of head and body                                        3      3
           interfemoral membrane                                0     3½
           the antibrachium                                     2      2
           thumb (claw included)                                0      8
           tibia                                                0     10
           tarsus (claw included)                               0     8⅓
           ear                                                  0      4
           tragus                                               0      3
           nose-leaf                                            0     2¼
 Expanse   the wings
   of                                                          12      8


  Habitat, Coquimbo, Chile. (_May._)


“The Vampire Bat,” says Mr. Darwin in his MS. notes upon the present
species, “is often the cause of much trouble, by biting the horses on
their withers. The injury is generally not so much owing to the loss of
blood, as to the inflammation which the pressure of the saddle
afterwards produces. The whole circumstance has lately been doubted in
England; I was therefore fortunate in being present when one was
actually caught on a horse’s back. We were bivouacking late one evening
near Coquimbo, in Chile, when my servant, noticing that one of the
horses was very restive, went to see what was the matter, and fancying
he could distinguish something, suddenly put his hand on the beast’s
withers, and secured the Vampire. In the morning, the spot where the
bite had been inflicted was easily distinguished from being slightly
swollen and bloody. The third day afterwards we rode the horse, without
any ill effects.”

Before the introduction of the domesticated quadrupeds, this Vampire Bat
probably preyed on the guanaco, or vicugna, for these, together with the
puma, and man, were the only terrestrial mammalia of large size, which
formerly inhabited the northern part of Chile. This species must be
unknown, or very uncommon in Central Chile, since Molina, who lived in
that part, says (Compendio de la Historia del Reyno de Chile, vol. i. p.
301,) “that no blood-sucking species is found in this province.”

It is interesting to find that the structure of this animal is in
perfect accordance with the habits as above detailed by Mr. Darwin.
Among other points, the total absence of true molars, and consequent
want of the power of masticating food, is the most remarkable. On the
other hand we find the canines and incisors perfectly fitted for
inflicting a wound such as described, while the small size of the
interfemoral membrane (giving freedom to the motions of the legs,)
together with the unusually large size of the thumb and claw, would
enable this Bat, as I should imagine, to fix itself with great security
to the body of the horse.

I have named this species after M. d’Orbigny, who has added so much to
our information on the zoological productions of South America. The
_Edostoma cinerea_[2] of that author has evidently a close affinity to
the animal here described, and differs chiefly (judging from the drawing
published in his work) in the larger size of the ears, in having the
nose-leaf free, and the surrounding membrane free and elevated.

As M. d’Orbigny has not yet published the character of his genus
_Edostoma_, his figure is my only guide, and in this figure I find the
dentition agreeing both with that of the present species, and that of
the genus _Desmodus_ of Prince Maximilian,—as would appear from the
published descriptions, and figure given by M. de Blainville[3].—The
points of distinction between M. d’Orbigny’s animal and the species here
described, are not, in my opinion, of sufficient importance to
constitute generic characters, I have, therefore, retained the name of
Desmodus.

It is desireable perhaps to separate the Blood-sucking Bats from the
Insectivorous species, and place them between the latter group and the
_Pteropina_, (with which they agree in the large size of the thumb and
the rudimentary interfemoral membrane,) under a sectional name, which I
propose to call _Hæmatophilini_.


                         1. PHYLLOSTOMA GRAYI.
                               PLATE II.

  _P. fusco-cinereum; nasûs prosthemate lanceolato; auribus mediocribus,
    trago basin versus extùs unidentato; caudâ gracillimâ, brevi, et
    membranâ interfemorali inclusâ; verrucâ complanatâ ad apicem menti,
    verrucis parvulis circumdatâ._

  DESCRIPTION.—This Phyllostoma agrees with the species described by Mr.
      J. Gray[4] under the name of Childreni, in having on the lower lip
      “an half ovate group of crowded warts,” but is of a much smaller
      size, and differs also in colour.

  The number of teeth are as follows:—incisors ⁴⁄₄; canines ²⁄₂; molars
      5⁵⁄₅–5 = 32. The intermediate pair of incisors of the upper jaw
      are large, compressed, and have their apices rounded; the lateral
      pair are so minute, that they are scarcely visible without the
      assistance of a lens: the four incisors of the lower jaw, are
      somewhat crowded, the intermediate pair are slightly larger than
      the lateral; they are all deeply notched, and broad at the apex.
      The cerebral portion of the skull is much arched and the anterior
      portion is depressed. The zygomatic arch is imperfect; see Pl. 35.
      figs. 2. The nose-leaf is lanceolate, and of moderate size: the
      ears are also of moderate size; they are rounded at the tip and
      emarginated on their exterior edge: the tragus is elongated, and
      suddenly attenuated towards the apex; the outer margin is deeply
      notched towards the base, and very obscurely crenulated above this
      notch. The interfemoral membrane is of moderate extent, and
      emarginated posteriorly. The tail, which is very slender, is
      entirely enclosed by the interfemoral membrane, and the visible
      portion appears to consist of but two joints, which together,
      measure about two and a half lines in length. The basal half of
      the thumb is enclosed in membrane. The fur is soft and rather
      long. The general tint of the upper and under parts of the body is
      brownish-ash; the hairs on the neck and on the whole of the back
      are grey at the base, then white, or nearly so, brownish-ash near
      the tip, and whitish at the tip. On the belly the hairs are nearly
      of an uniform brown-ash colour, their apices only being whitish.
      The ears, nose-leaf, and membrane of the wings, are of a
      sooty-black hue.

                                                              In. Lines.
 Length of head and body                                        2      0
           antibrachium                                         1     4⅓
           thumb (claw included)                                0     5½
           tibia                                                0      7
           ear                                                  0      7
           nose-leaf                                            0     3⅓
 Expanse   the wings
   of                                                          10      0


  Habitat, Pernambuco, Brazil. (_August._)


“This species appeared to be common at Pernambuco (five degrees north of
Bahia). Upon entering an old lime-kiln in the middle of the day, I
disturbed a considerable number of them: they did not seem to be much
incommoded by the light, and their habitation was much less dark than
that usually frequented as a sleeping place by these animals.” D.

I have named this species after Mr. John Gray, the author of several
extensive memoirs on the order to which it belongs, and to whom I am
indebted for valuable assistance whilst comparing this and other species
with those contained in the collection of the British Museum.


                     2. PHYLLOSTOMA PERSPICILLATUM.

I find in Mr. Darwin’s collection, a bat agreeing with the description
of M. Geoffroy Saint Hilaire,[5] under the above name, with the
exception of a slight difference in the dimensions; I will, therefore,
add those of the present specimen, which is a female. It may be
observed, that in the animal before me, the tragus of the ear is
pointed, and not bifid at the apex, as represented in plate xi of the
work quoted.

                                                              In. Lines.
 Length of head and body                                        4      0
           antibrachium                                         2      7
           nose-leaf                                            0      5
           ear                                                  0     8½
           tragus                                               0      3
           tibia                                                1      0
 Expansion the wings
   of                                                          16      8

“This bat was caught at Bahia, (latitude 13° S.) on the coast of Brazil,
in consequence of its having flown into a room where there was a light.
I scarcely ever saw an animal so tenacious of life.” D.




                        FAMILY—VESPERTILIONIDÆ.


                        VESPERTILIO CHILOENSIS.
                               PLATE III.

  _V. fuscus: auribus mediocribus; trago elongato, angusto, apicem
    versus attenuato; fronte concavo; rostro obtuso; caudâ ad apicem
    extremum liberâ._

  DESCRIPTION.—In size and colouring, this Bat very closely resembles
      the _Vespertilio Pipistrellus_ of Europe; the wings, however, are
      considerably broader in proportion; the antibrachium, tibia, and
      tail, are each of them longer; the tragus of the ear is also
      longer, and narrower.

  The muzzle is short and obtuse, and furnished on each side with
      numerous hairs, which, when compared with those of other parts,
      are of a more harsh nature. The nose is naked at the apex. The
      forehead is concave. The ears are narrow, and somewhat pointed,
      emarginated externally, and have about four transverse rugæ: the
      tragus is elongated, narrow, and pointed, and has the outer margin
      very obscurely crenulated. On the chin there is a small wart, from
      which spring several stiffish hairs. The tail is about equal to
      the body in length, and has the extreme tip free. The fur is
      moderately long, and of an uniform rich brown colour, and extends
      on to the base of the interfemoral membrane above and below; the
      remainder of this membrane is bare, and, together with that of the
      wings, of a black colour.

                                                              In. Lines.
 Length of the head and body                                    1      8
           the tail                                             1     3½
 Expanse   the wings
   of                                                           8      3
 Length of the ear                                              0     5½
           the tragus                                           0     3⅓
           the antibrachium                                     1     5½
           the thumb (claw included)                            0     2½
           the tibia                                            0     6¾


  Habitat, Chiloe. (_January._)


“This specimen was given me by Lieut. Sulivan, who obtained it amongst
the islets on the Eastern side of Chiloe. It is not, I believe, common,
nor do the humid and impervious forests of that island appear a
congenial habitation for members of this family. It must, however, be
observed, that even in Tierra del Fuego, where the climate is still less
hospitable, and where the number of insects is surprisingly small, I saw
one of these animals on the wing.” D.




                          FAMILY—NOCTILIONIDÆ.


                            DYSOPES NASUTUS.

  Molossus nasutus _Spix_, Simiarum et Vespertilionum. Braziliensium
  species novæ. Nyctinomus Braziliensis.—_Geoffroy_, Annales des
  Sciences Naturelles, tom. i. p. 337. pl. 22.

Of this species I find three specimens in Mr. Darwin’s collection—“It is
remarkable,” says Mr. Darwin, “for its wide geographical range. I
obtained specimens at Maldonado, on the northern bank of the Plata,
where it was exceedingly numerous in the attics of old houses, and
likewise at Valparaiso in Chile. Molina (vol. i. p. 301.) says another
species is found in Chile, of the same size and figure, but of a more
orange (_naranjado_) colour.”

Upon comparing the dimensions of several specimens of this species with
those given by Temminck in his “Monographie sur le Genre Molosse,” I
find that they vary very considerably; I shall therefore be adding some
little to the history of the species, by giving the dimensions of those
now before me, together with the sexes of the specimens measured, and
their localities. In all these specimens there is a series of pointed
tubercles along the upper margin of the ears, a character which M.
Temminck has omitted to notice. They vary slightly in the intensity of
their colouring, but among those brought from Chile I do not perceive
any agreeing with that species, or variety, mentioned by Molina as
approaching to an orange colour. All the specimens whose dimensions are
here given, are preserved in spirit. Two of them are from Maldonado
brought by Mr. Darwin; three were collected in Hayti by Mr. J. Hearne,
and one is from Chile, whence it was brought by Mr. H. Cuming.

                                  From Chile.   Hayti.      Hayti.
                                       ♀           ♀           ♂
                                   In. Lines.  In. Lines.  In. Lines.
 Length  of head and body            2      3    1     11    2      0
         of tail                     1     1½    1      2    1      2
         of free portion of ditto    0     6½    0      5    0     6½
 Expanse of wings                   10      3    9      3    9      8
 Length  of antibrachium             1      7    1      6    1     6½
         of ears                     0      5    0     4½    0     4¾
 Width   of ditto                    0      7    0      6    0      6
 Length  from nose to eye            0     3½    0      3    0     3¾

                                    Hayti.    Maldonado.  Maldonado.
                                       ♂           ♀           ♀
                                   In. Lines.  In. Lines.  In. Lines.
 Length  of head and body            2     0½    2      6    2      6
         of tail                     1     1½    1      1    1      2
         of free portion of ditto    0     5⅓    0     8¾    0     8½
 Expanse of wings                    9      0   10      6   10      2
 Length  of antibrachium             1      6    1      8    1      9
         of ears                     0     4½    0     5⅛    0     5½
 Width   of ditto                    0      6    0      7    0      7
 Length  from nose to eye            0      3    0     3½    0     3½

In all the specimens examined by me, there are two incisors in the upper
jaw, and four in the lower, they would therefore, according to M.
Temminck, be adult.




                           FAMILY—CARNIVORA.


                         1. CANIS ANTARCTICUS.
                               PLATE IV.

  Antarctic Wolf, _Pennant_, History of Quadrupeds, vol. i. p. 257. sp.
  165.

  Canis Antarcticus, _Shaw_, Gen. Zool. vol. i. pt. 2. p. 331.

  ——, _Desm._ Mamm. p. 199.

  _C. suprà sordidè fulvescenti-brunneus, pilis ad apicem nigris;
    lateribus, corporeque subtùs, sordidè flavescenti-fuscis; capite,
    auribusque extùs, fusco nigroque adspersis; artubus
    flavescenti-fulvis; labiis, gulâ, abdomine imo, femoribusque intùs,
    sordidè albis; caudâ ad basin concolore cum corpore, deìn nigrâ,
    apice albo._

  DESCRIPTION.—This animal is considerably larger than the common fox,
      (_Canis Vulpes_, Auct.) and stouter in its proportions, and, in
      fact, appears to be intermediate between the ordinary foxes and
      the wolves. The tail is much smaller and less bushy than in the
      former animals. The contour of the head is wolf-like; the legs,
      however, are shorter than in the true wolves; and the tail is
      white at the apex, a character common in the foxes.

  The fur of the Antarctic Fox is moderately long, and the under fur is
      not very abundant, especially as compared with that of the C.
      _magellanicus_. This under fur is of a pale brown colour; the
      apical portion of each hair is yellowish; the longer hairs are
      black at the apex, brown at the base, and annulated with white
      towards the apex. In many of these hairs the subapical pale ring
      is wanting. On the chest and belly the hairs are of a pale dirty
      yellow colour, gray-white at the base, and black at the apex. On
      the hinder part of the belly the hairs are almost of an uniform
      dirty white. The space around the angle of the mouth, the upper
      lip, and the whole of the throat, are white. The chin is
      brown-white, or brownish. The basal half of the tail is of the
      same colour as the body, and the hairs are of the same texture; on
      the apical half of the tail they are of a harsher or less woolly
      nature, of a black colour at the apex, and brownish at the base;
      those at the extreme point are totally white. The legs are almost
      of an uniform fulvous colour; the feet are of a somewhat paler
      hue; the hairs on the under side of the hinder feet are brownish,
      and the external and posterior parts of the tibiæ are suffused
      with the same tint. The hairs on the head are grizzled with black
      and fulvous; the former of these colours is somewhat conspicuous,
      excepting in the region of the eyes, where the fulvous or
      yellowish tint prevails. The muzzle is scarcely of so dark a hue
      as the crown of the head. The ears are furnished internally with
      long white hairs, externally the hairs are yellowish, with their
      apices black; the latter colour is more conspicuous towards the
      tip of the ear. The sides of the neck near the ear are of a rich
      fulvous hue.

                                                              In. Lines.
 Length    from nose to root of tail                           36      0
           from tip of nose to ear                              7      3
           of tail (hair included)                             13      0
           of ear                                               2      9
 Height    of body at shoulders                                15      0


  Habitat, Falkland Islands.


Three specimens of this animal were brought to England by Capt. FitzRoy;
from one of which, the above drawing and description has been made. The
earliest notice I can find of this animal is by Pernety,[6] during
Bougainville’s voyage, which was undertaken in 1764, for the purpose of
colonizing these islands. The strange familiarity of its manner seems to
have excited the fears of some of the seamen in Commodore Byron’s voyage
(in 1765) in rather a ludicrous manner. Byron says that seals were not
the only dangerous animals that they found, “for the master having been
sent out one day to sound the coast upon the south shore, reported at
his return that four creatures of great fierceness, resembling wolves,
ran up to their bellies in the water to attack the people in his boat,
and that as they happened to have no fire-arms with them, they had
immediately put the boat off in deep water.” Byron adds that, “When any
of these creatures got sight of our people, though at ever so great a
distance, they ran directly at them; and no less than five of them were
killed this day. They were always called wolves by the ship’s company,
but, except in their size, and the shape of the tail, I think they bore
a greater resemblance to a fox. They are as big as a middle-sized
mastiff, and their fangs are remarkably long and sharp. There are great
numbers of them upon this coast, though it is not perhaps easy to guess
how they first came hither; for these islands are at least one hundred
leagues distant from the main. They burrow in the ground like a fox, and
we have frequently seen pieces of seals which they have mangled, and the
skins of penguins lie scattered about the mouths of their holes. To get
rid of these creatures, our people set fire to the grass, so that the
country was in a blaze as far as the eye could reach, for several days,
and we could see them running in great numbers to seek other quarters.”

“The habits of these animals remain nearly the same to the present day,
although their numbers have been greatly decreased by the singular
facility with which they are destroyed. I was assured by several of the
Spanish countrymen, who are employed in hunting the cattle which have
run wild on these islands, that they have repeatedly killed them by
means of a knife held in one hand, and a piece of meat to tempt them to
approach, in the other. They range over the whole island, but perhaps
are most numerous near the coast; in the inland parts they must subsist
almost exclusively on the upland geese, (_Anser leucopterus_,) which,
from fear of them, like the eider-ducks of Iceland, build only on the
small outlying islets. These wolves do not go in packs; they wander
about by day, but more commonly in the evening; they burrow holes; are
generally very silent, excepting during the breeding season, when they
utter cries, which were described to me as resembling those of the
_Canis Azaræ_. Spaniards and half-caste Indians, from several districts
of the southern portions of South America, have visited these islands,
and they all declare that the wolf is not found on the mainland; the
sealers likewise say it does not occur on Georgia, Sandwich Land, or the
other islands in the Antarctic ocean. I entertain, therefore, no doubt,
that the _Canis antarcticus_ is peculiar to this archipelago. It is
found both on East and West Falkland, as might have been inferred from
the accounts given by Bougainville and Byron, who visited different
islands;—I state this particularly, because the contrary has been
asserted. I was assured by Mr. Low, an intelligent sealer, who has long
frequented these islands, that the wolves of West Falkland are
invariably smaller and of a redder colour than those from the Eastern
island; and this account was corroborated by the officers of the
Adventure, employed in surveying the archipelago. Mr. Gray, of the
British Museum, had the kindness to compare in my presence the specimens
deposited there by Captain Fitzroy, but he could not detect any
essential difference between them. The number of these animals during
the last fifty years must have been greatly reduced; already they are
entirely banished from that half of East Falkland which lies East of the
head of St. Salvador Bay and Berkeley Sound; and it cannot, I think, be
doubted, that as these islands are now becoming colonized, before the
paper is decayed on which this animal has been figured, it will be
ranked amongst those species which have perished from the face of the
earth.”—D.


                         2. CANIS MAGELLANICUS.
                                PLATE V.

 Canis Magellanicus, _Gray_, Proceedings of the Zoological Society of
    London, part iv. 1836, p. 88.
 Vulpes Magellanica, _Gray_, Magazine of Natural History, New Series,
    1837, vol. i. p. 578.

  _C. suprà albo nigroque variegatus; lateribus fulvescente fuscoque
    lavatis; capite fusco-flavo et albescente adsperso; rostro supernè
    obscuriore; auribus, artubusque extùs flavescenti-rufis; corpore
    subtùs sordidè flavescenti-albo; pectore fulvo lavato; mento
    fuscescente; caudâ fulvescenti-fuscâ, pilis ad apicem nigris, subtùs
    pallidiore; plagâ supernè prope basin caudæ, hujusque apice nigris._

  DESCRIPTION.—This species is considerably larger than the European
      fox; its form is more bulky, the limbs are shorter and stouter in
      proportion, the ears are smaller and the tail is more bushy. The
      fur is long, thick, and loose. The under fur is very long,
      abundant, and of a woolly texture. The back is mottled with black
      and white, the former of these colours being predominant; the
      hairs on this part are gray at the base, there is then a
      considerable space of a pale, or whitish brown colour; next
      follows a broad white ring, beyond which the hairs are black. On
      the sides of the body the hairs are coloured in the same way,
      excepting that the white portion is more extended, and is followed
      by a rich yellow-brown, shaded into black as it approaches the
      apex of each hair. Hence the general hue of the sides of the body
      is paler than that of the back, the brown and white tints being
      the more conspicuous. The hairs of the head are annulated with
      white, and fulvous, and are black at the tip; the two former
      colours are most conspicuous. The chin is brownish. The lower part
      of the cheeks, the throat, and the under parts of the body, are of
      a dirty yellowish white colour, inclining to buff in certain
      parts, especially on the lower part of the neck and chest. The
      limbs are of a rich deep fulvous, or yellowish rust colour
      externally; the feet and inner sides of the legs are of a paler
      hue. On the hinder legs externally, above the heel, is a patch of
      bright rust colour; such is also the colour of the ears
      externally, and likewise of that portion of the neck behind the
      ears. Internally the ears are furnished with long yellowish white
      hairs. The tail is long and very bushy; at its base the hairs are
      rusty white, towards the middle they are of a paleish rust colour,
      and at the apex they are black; there is also a black patch on the
      upper part towards the base. The hairs of the tail beneath are
      almost entirely of an uniform rusty white colour, those on the
      upper side are all tipped with black.

                                                              In. Lines.
 Length    from nose to root of tail                           31      0
                                               to base of ear   6      9
           of tail (hair included)                             17      0
           of ear                                               2      0
 Height    of body at the shoulders                            14      6


  Habitat, Chile. (_June._)


“This animal was first brought to Europe by Captain Philip P. King, who
obtained it at Port Famine in Tierra del Fuego, where it is common. My
specimen was obtained in the valley of Copiapó in the northern part of
Chile. The Magellanic fox, therefore, has a range on the western coast
of at least 1600 miles, from the humid and entangled forests of Tierra
del Fuego, to the almost absolutely desert country of northern Chile. In
La Plata, on the Atlantic side of the continent, I believe it is not
found.[7] It is mentioned by Molina in his account of the animals of
Chile,[8] under the name of Culpeu, which he supposes to be derived from
the Indian word “culpem,” signifying madness; for this animal, when it
sees a man, runs towards him, and standing at the distance of a few
yards, looks at him attentively. He adds, although great numbers are
killed, they do not leave off this habit. Molina states that he has
repeatedly been a witness of this, and I received nearly similar
accounts from several of the inhabitants of Chile: yet I must observe,
that the people of the farm-house, where my specimen was killed (after
it, together with its female, had destroyed nearly two hundred fowls)
bitterly complained of its craftiness. From this bold curiosity in the
disposition of the Culpeu, Molina thought that it was the same animal as
that described by Byron at the Falkland Islands, but we now know that
they are different. The Culpeu burrows holes under ground, often wanders
about by day, is very strong and fleet. When riding one day in the
valley of Copiapó, accompanied by a half-bred greyhound, I happened to
come across one of these foxes; and although the ground was, in the
first part of the chase, level, it soon entirely distanced its pursuer.
Whilst running, it barked so like a dog, that until it had run some way
a-head of the greyhound, I could not tell from which animal the noise
proceeded. After the Culpeu had reached the mountains, it made a sudden
bend from its course, and returned in a nearly parallel line, but at the
base of a steep cliff of rock; it then quietly seated itself on its
haunches, and seemed to listen with much satisfaction to the dog, which
was running the scent on the mountain side, above its head.”—D.


                           3. CANIS FULVIPES.
                               PLATE VI.

 Canis fulvipes, _Martin_, Proceedings of the Zoological Society of
    London, 1837, p. 11.

  _C. suprà niger, albo adspersus, capite lateribusque fuscis, sordidè
    albo nigroque adspersis; rostro superiore, mentoque
    fusco-nigricantibus; gulâ, labiis superioribus, femoribusque ad
    partem anteriorem, sordidè albis; pectore abdomineque
    fuscescentibus; auribus externè rufo-castaneis; brachiis internè,
    tarsis, digitisque fuscescenti-fulvis; artubus posticis extùs supra
    calcem fusco-nigrescentibus; caudæ colore ad basin ut in corpore,
    apice nigro._

  DESCRIPTION.—This species is considerably less than the common
      European fox, (_Canis Vulpes_, Auct.) its weight probably would
      scarcely exceed half that of the latter animal. The form of the
      body is stout, the limbs are short and rather slender; the head is
      also short, and the muzzle is pointed; the ears are of moderate
      size. The tail is about equal to half the whole length of the
      body, head included; and compared with that of ordinary foxes, is
      much less bushy, especially at the base. The general hue of this
      animal is very dark; the fur is rather short, and harsh to the
      touch; the under fur is abundant, and of a woolly texture. On the
      back, all the hairs are of a deep brown colour, annulated with
      white near the apex, and black at the apex. When the fur is in its
      ordinary position, the brown colour is not seen, and the black and
      white produce a grizzled appearance; the black colour, however,
      predominates. On the sides of the body each hair is grayish at the
      base, then pale brown, near the apex annulated with white, and at
      the apex black: the three last mentioned colours are exhibited in
      about equal proportions (the fur being in its natural position)
      over the haunches and shoulders, but between these two parts, the
      brown and white colours are the more conspicuous. The hairs of the
      head are coloured in the same way as those of the sides of the
      body, excepting that the brown portion of each hair, is replaced
      by rusty brown, which gives a rufous hue to this part. The muzzle
      and chin are of a sooty brown colour. A dirty white patch is
      observable on each side of the muzzle at the apex, and this colour
      is extended along the margin of the upper lip on to the lower part
      of the cheeks, and over the whole of the throat; all the hairs in
      these parts (with the exception of those on the lips) being of a
      deep brownish gray colour, with their apical portions only, white.
      The ears are covered internally with long yellowish white hairs;
      towards, and on the margin of the ears externally, the hairs are
      of a buff colour, on the remaining portion of the ears, and on the
      sides of the neck, they are of a reddish chestnut hue. The hairs
      of the under parts of the body are brown, those near the hinder
      legs, and between them, are of a dirty white colour at the apex;
      towards the rump they are of a yellowish brown colour. The hairs
      of the tail are brown, black at the apex, and annulated with white
      near the apex; on the apical portion the hairs are black, and
      brown at the base. The fore legs are of a brown colour externally,
      internally they are of a brownish fulvous hue; such is also the
      colour of the feet. The fore part of the posterior legs is
      whitish, and there is a large blackish patch on the outer side,
      and extending around the posterior part, above the heel.

                                                              In. Lines.
 Length    from nose to root of tail                           24      0
                                               to base of ear   0     4¾
           of tail (hair included)                             10      0
           of ear                                               2     3½
 Height    of body at the shoulders                            10      6


  Habitat, Chiloe. (_December._)


“I killed this animal on the sea-beach, at the southern point of the
island; it is considered extremely rare in the northern and inhabited
districts. Molina mentions this fox, which he falsely considered as the
_C. lagopus_, under the name of the _Payne Gurú_, and he adds, that in
the Archipelago of Chiloe, it is found of a black colour. From this
circumstance I am induced to believe that the species is confined to
these islands.”—D.


                            4. CANIS AZARÆ.
                               PLATE VII.

  Canis Azaræ, _Pr. Maximilian_, Beiträge zur Naturgeschichte
  Braziliens, vol. ii. p. 338.

  Agouarachay, _Azara_, Essais sur l’histoire naturelle des Quadrupèdes
  de la Province du Paraguay, tom. i. p. 317.

  _C. suprà albo nigroque variegatus; lateribus cinerescentibus; capite,
    auribus externè, artubusque, cinereo-cinnamominis; mento nigro;
    tibiis externis ad basin nigro lavatis; caudâ albescente, suprà
    nigro variegatâ, ad apicem nigrâ; spatio pone angulos oris, gutture,
    corporeque subtùs albescentibus; fasciis duabus griscescentibus in
    pectore plus minusve distinctis._

  DESCRIPTION.—Compared with the common fox (_Canis Vulpes_, Auct.), the
      present animal is rather smaller, and of a more slender form. Its
      limbs are a little longer in proportion; the ears are not so
      broad. The tail is not quite so bushy, neither is it so long; the
      fur is much longer, and of a harsher nature.

  The predominant colours of the body are black and white; the limbs are
      of a fulvous hue externally. The hairs on the under part of the
      feet are dirty brown; the fore part of the anterior legs, and the
      feet, are of a buff colour; on the former, the hairs are more or
      less distinctly tipped with black, which produces a grizzled
      appearance. The inner side of the fore legs is of an uniform pale
      buff colour; the hinder part of these legs, the fore part of the
      posterior legs, and the inner side of the thighs, are white. On
      the outer side of the hinder legs, at some little distance above
      the heel, is a large blackish patch. The under parts of the body
      are of a dirty white hue, arising from the hairs being dusky or
      brownish at the base, and tipped with white, as on the fore part
      of the belly, or of a pale buff colour at the base, as towards the
      rump. The edge of the upper lip, the throat, neck, and chest, are
      white; a broad grayish band extends across the latter, and another
      of a paler hue crosses the lower part of the neck. The chin is
      black, and this colour is extended backwards around the angle of
      the mouth. The upper part of the head is of a pale yellow-brown
      colour, each hair being annulated with white near the apex. The
      ears are furnished with white hairs internally, and externally
      they are of a yellowish brown colour, tipped with black; at the
      base of the ears, and the portion of the neck on each side nearest
      to them, the hairs are of an uniform buff colour. The hairs of the
      moustaches are long and stiff, and of a black colour. The hairs of
      the back, which are very long, are brown at the base, very pale
      towards the skin, and of a deep brown in the opposite direction;
      each hair is then white, and at the apex black. The tail is
      whitish, mottled with black; the apical portion is black, and
      there is a patch of the same colour towards the base on the upper
      side.

                                                              In. Lines.
 Length    from nose to root of tail                           27      6
                                               to base of ear   5      9
           of tail (hair included)                             14      6
           of ear                                               3      2
 Height    of body at the shoulders                            14      0


  Habitat, La Plata, Patagonia, and Chile.


The black and white portions of the hairs on the back produce in that
part a mottled appearance, and in the specimen from which the above
description is taken, these two colours are about equal in proportion.
In another specimen now before me, the black colour predominates on the
back. The fur in the younger animals of this species is not so long nor
so harsh, and the upper parts are grizzled with black and white; that is
to say, these two colours do not form patches of considerable extent as
in the adults; the general colouring is also somewhat paler. The chin is
brown-black or brown, instead of black, and the upper band, or that,
which in the adult extends across the upper part of the neck, is
interrupted in the middle; in fact, is only traceable on the _sides_ of
the neck.

Azara, in his description of the Agouarachay, says, the muzzle, as far
back as the eyes, is blackish; whereas, in all the specimens examined by
me, the muzzle is of the same colour as the other parts of the head, or
_very_ nearly so. In other respects his description agrees with the
animal described by me, and _not_ with the _Canis cinereo-argentatus_,
which Desmarest and Lesson suppose to be the Agouarachay of Azara. In
Fischer’s “_Synopsis Mammalium_” the _Canis Azaræ_ is described as
having the tip of the tail white; whereas it is black, not only in the
five specimens which have come under my notice, but also in those in the
collection of Prince Maximilian[9] (who was the original describer) and
in the Paris Museum.

“This animal has a wide range; Prince Maximilian brought specimens from
Brazil; and it is common in La Plata, Chile, the whole of Patagonia,
even to the shores of the Strait of Magellan; and a fox, which lives on
the small islands not far from Cape Horn, probably belongs to this
species. This animal generally frequents desert places; I saw many in
the valley of the Despoblado, a branch of that of Copiapó, where there
is no fresh water, and where, with the exception of some small rodents,
(the constant inhabitants of sterile regions) scarcely any other animal
could exist. I saw also very many of these foxes wandering about by day
(although Azara says they are nocturnal in Paraguay) on the plains of
Santa Cruz, where various kinds of mice are abundant, and likewise
around the Sierra Ventana. In the course of one day’s ride in this
latter neighbourhood, (not far from Bahia Blanca, lat. 39° S.) I should
think I saw between thirty and forty. They generally were wandering at
no great distance from their burrows; but, as they are not very swift
animals, our dogs caught two. Azara states that in Paraguay this fox,
which he calls the Agourá-chay, inhabits thick woods, and that it makes
a great nest or pile of straw, to lie on; but that near Buenos Ayres it
uses the holes of the Bizcacha. Further southward, where the Bizcacha is
not found, it certainly excavates its own burrow.[10] In Chile these
foxes are very destructive to the vineyards, from the quantity of grapes
they consume; so that boys are generally kept in the vintage season with
bells and other means to frighten them away. Azara states, that in
Paraguay they likewise eat fruit and sugarcane. By the same authority it
is said, that the Agourá-chay, when taken young, is easily
domesticated.”—D.


                         1. FELIS YAGOUAROUNDI.
                              PLATE VIII.

  Felis Yagouaroundi, _Desmarest_, Mammologie, p. 230.

  Yagouaroundi, _Azara_, Essais sur l’histoire Naturelle des Quadrupèdes
  de la Province du Paraguay, tom. i. p. 171.

  Felis Darwinii, _Martin_, Proceedings of the Zoological Society of
  London, 1837, p. 3.

  _F. vellere brevi, adpresso, purpurascenti-fusco; pilis flavescente
    annulatis; pedibus nigro lavatis; caudâ longissimâ; auribus
    parvulis._

  DESCRIPTION.—The fur is rather harsh, short, and somewhat adpressed:
      the under fur is of a pale grayish brown colour; the hairs which
      constitute the chief clothing of the animal, are black, annulated
      with brownish yellow, or in some parts, yellow-white, each hair
      having about three or four rings. The black and pale colours are
      about equal in proportion, and their mixture produces a deep brown
      tint, which is almost uniform throughout the body and limbs. On
      the head the yellowish colour predominates over the black,
      excepting on the tip of the muzzle, and thence back to the eye,
      where the hairs are of a brownish black colour. On the throat the
      hairs are brown. The underside of the tarsus is black, and on the
      outer side of the fore foot there is a black mark which extends
      upwards on to the wrist. The tail is long and bushy; towards and
      on the base, the hairs are annulated with black and yellow, like
      those of the body; but beyond this they are of a more uniform
      colour, each hair being brown at the base, and gradually shaded
      into black towards the tip. The ears are small and rounded, and
      covered with hairs of the same colour as those on the head. The
      claws are of a large size, and white colour; the toes are united
      for a considerable portion of their length by the interdigital
      membrane.

                                                              In. Lines.
 Length    from nose to root of tail                           25      0
                                               to base of ear   3      6
           of tail (hairs included)                            19      0
           of ear                                               1      0
 Height    of body at shoulders                                12      0


  Habitat, Rio de Janeiro, Brazil. (_May._)


“This cat was given me by an old Portuguese priest, who had hunted it
down in a thick forest with a small pack of dogs, after a severe chase.
It was killed near the Gavia mountain, at the distance of a few miles
only from Rio de Janeiro, where it was considered uncommon.” D. Although
small, compared with the Puma, (_Felis concolor_, Auct.), this cat, in
its slender lengthened body, small head, long tail, and stout limbs,
decidedly evinces an affinity to that species. According to the
dimensions of the Yagouaroundi given by Azara, Desmarest, and Temminck,
it appears that the tail is considerably shorter in proportion in the
specimens examined by those naturalists, than in the present individual,
and the difference was such, as to induce Mr. Martin to believe that the
latter was a distinct species; he accordingly proposed for it the
specific name of _Darwinii_. At the time that Mr. Martin described the
specimen alluded to, I was also inclined to believe it was a distinct
species. I mention this because I am afraid my opinion had a slight
share in influencing Mr. Martin’s determination. I have since seen many
specimens, and upon comparing their dimensions, I find that the
proportionate length of the tail varies more than is usual in other
species of cats, and that the difference in the length in this member is
not combined with any other distinguishing character. In colouring there
is also a considerable variation, some specimens being almost black, and
having the hairs but obscurely annulated with white; in others, the
hairs are more distinctly annulated, and the head assumes a grayish hue.
Others again, are brown, or black brown, having the hairs annulated with
yellow. The following are the dimensions of two specimens in the Paris
museum, and those given by the authors above alluded to.[11]

               _Paris M._ _Paris M._ _Desmarest._ _Temminck._  _Azara._
               In. Lines. In. Lines.   In. Lines.  In. Lines. In. Lines.
 Length from
          nose
          to
          root
          of
          tail  30      6  28      0    23      0   30      0  36      9
            of
          tail  24      0  17      0    13      9   22      0  13      9


                           2. FELIS PAJEROS.
                               PLATE IX.

  Chat Pampa, _Azara_, Essais sur l’histoire Naturelle des Quadrupèdes
  du Paraguay. Traduct. Franç. tom. 1. p. 179.

  Felis Pajeros, _Desmarest_, Mammologie, p. 231.

  _F. vellere longissimo, flavescenti-griseo, fasciis flavescenti-fuscis
    indistinctè et sublongitudinalitèr notato; pedibus annulis latis
    nigris; abdomine maculis magnis nigris; mento albo; caudâ brevi;
    auribus mediocribus, ad apicem externum nigris._

  DESCRIPTION.—The Pampas cat is about equal in size to the common wild
      cat of Europe (_Felis Catus_, Linn.). It is however of a stouter
      form than that animal, the head is smaller, and the tail is
      shorter.

  The most remarkable character in this species consists in the great
      length of the fur,—the longer hairs on the back measuring upwards
      of three inches, and those on the hinder part of the back, are
      from four and a half, to four and three quarter inches in length.
      The general colour of the fur is pale yellow-gray. Numerous
      irregular yellow, or sometimes brown stripes run in an oblique
      manner from the back along the sides of the body. On each side of
      the face there are two stripes of a yellowish or cinnamon colour:
      these stripes commence near the eye, extend backwards and
      downwards over the cheeks, on the hinder part of which they join
      and form a single line, which encircles the lower part of the
      throat. The tip of the muzzle and the chin are white, and there is
      a spot in front of the eye, and a line beneath the eye, of the
      same colour: the belly and the inner side and hinder part of the
      fore legs are also white. An irregular black line runs across the
      lower part of the chest and extends over the base of the fore legs
      externally, and above this line there are two other transverse
      dark markings on the chest, which are more or less defined. On the
      fore legs there are three broad black bands, two of which encircle
      the leg, and on the posterior legs there are about five black
      bands externally, and some irregular dark spots internally. The
      feet are yellowish, and the underside of the tarsus is of a
      slightly deeper hue. On the belly there are numerous large
      irregular black spots. The ears are of moderate size, furnished
      internally with long white hairs; externally, the ears are of the
      same colour as the head, excepting at the apex where the hairs are
      black and form a slight tuft. The tail is short, somewhat bushy,
      and devoid of dark rings or spots—the hairs are in fact coloured
      as those of the back of the animal. On the upper part of the body
      each hair is brown at the base, then yellow, and at the apex,
      black. On the hinder part of the back the hairs are almost black
      at the base, and on the sides of the body each hair is gray at the
      base; there is then a considerable space of yellowish white
      colour; towards the apex they are white, and at the apex black.
      The greater number of the hairs of the moustaches are white.

                                                              In. Lines.
 Length    from nose to root of tail                           26      0
                                               to base of ear   3      6
           of tail (fur included)                              11      0
           of ear                                               1     11
 Height    of body at shoulders                                13      0


  Habitat, Santa Cruz, Patagonia, (_April_,) and Bahia Blanca,
  (_August_).


The markings in this animal vary slightly in intensity; those on the
body are generally indistinct, but the black rings on the legs are
always very conspicuous.

“This animal takes its name from ‘paja,’ the Spanish word for straw,
from its habit of frequenting reeds. It is common over the whole of the
great plains, which compose the eastern side of the southern part of
America. According to Azara, it extends northward as far as latitude
30°, and to the south, I have reason to believe, from the accounts I
have received, that it is found near the Strait of Magellan, which would
give it a range of nearly 1400 miles, in a north and south line. One of
my specimens was obtained, in 50° south, at Santa Cruz: it was met with
in a valley, where a few thickets were growing. When disturbed, it did
not run away, but drew itself up, and hissed. My other specimen was
half-grown, and was killed in the end of August, at Bahia Blanca.”—D.


                          3. FELIS DOMESTICA.

  Felis domestica, _Brisson_, Reg. Anim. p. 264.

I find in Mr. Darwin’s collection a cat, the colouring and proportions
of which, convince me that its origin is from the domestic cat, as
however it was shot in a wild state far from any house, a description
may, perhaps, prove useful. Its general colour is deep gray, and the
body is adorned with numerous irregular narrow black bands; there is a
broad black mark, formed of confluent spots, along the middle of the
back, which commences a little behind the shoulders; a considerable
space around the angles of the mouth, the chin, throat, central portion
of the chest, fore feet, toes of the hinder feet, and the posterior
portion of the belly, are white; a black line extends backwards from the
posterior angle of the eye, on to the cheeks; thence, across the throat,
there are two lines: the space between the eye is chiefly occupied with
white hairs: the tail is slender, and tapers towards the apex; the basal
half is gray with black rings, and the apical half is black, excepting
the extreme point, which is white: the tarsus is black beneath: the legs
are of a deep gray colour, banded with black externally.

To the dimensions I will add those of a domestic cat which in colour and
markings very closely resembles the animal above described. I may add
that I have chosen a cat rather above the ordinary size for my
comparison, yet it will be seen that the wild cat has the advantage in
bulk.

                                     Wild Cat.        Domestic Cat.
                                        In. Lines.           In. Lines.
 Length from nose to root of tail        22      0            19      0
        of tail                          12      3            11      6
        of tarsus                         5      1             4      7
        of ear                            1     11
 Height at shoulders                     11      3


  Habitat, Maldonado, La Plata, (_May._)


“This animal was killed amongst some thickets on a rocky hill a few
miles from Maldonado. It appeared, when dead, much larger and stronger
than any domestic cat I ever saw, and it was described to me as having
been exceedingly fierce. I mention this because M. Temminck supposes
that the domesticated varieties of all animals are of larger size, than
the wild stock from which they are descended.”—D.[12]


                           GALLICTIS VITTATA.

  Gallictis vittata, _Bell_, Zoological Journal, vol. ii. p. 551–2.

  ——, „ Proceedings of the Zoological Society, for April, 1837, p. 39.

  Gulo vittatus, _Desmarest_, Mamm. p. 175.

“This animal is not uncommon at Maldonado, where it is called “_Huron_”
or thief, from the ravages it commits on eggs and poultry. Shortly after
being killed this specimen weighed 1 lb. 8 oz. (Imp. weight).”—D.


                          1. LUTRA PLATENSIS.


  _L. vellere nitido, adpresso, intensè fusco; corpore subtùs
    pallidiore; gutture ad latera, et subtùs, pallidè fusco;
    mento rostrique apice sordidè flavescenti-albis; pedibus
    nigrescenti-fuscis; pilis caudæ supernè brevioribus, adpressis,
    illis ad caudæ latera longioribus et fimbriam efficientibus._

  DESCRIPTION.—This Otter is about equal in size to the common European
      species (_Lutra vulgaris_, Auct.): its fur is short, glossy, and
      adpressed; the under fur is tolerably abundant and of a silky
      nature. The general colouring of the ordinary fur is deep brown,
      and that of the under fur is very pale brown, deeper externally.
      The tint of the under parts of the body is paler than the upper,
      and may be described as brown, that of the throat, sides and under
      part of the neck, pale brown; and, on the tip of the muzzle and
      chin, dirty yellowish white. The hairs of the moustaches are
      brownish-white; the ears are covered with short deep brown hairs,
      those towards the tip are paler. The hairs covering the feet above
      are short, and of a very deep brown colour. The tail is tolerably
      long, thick at the base, whence it gradually tapers to the apex.
      The hairs on the base of the tail resemble those of the body, but
      on the remaining portion, they are short, glossy, and very closely
      applied to the skin both on the upper and under surface, whereas
      those on the sides are longer, and form a kind of fringe. The tip
      of the muzzle and the soles of the feet are naked, with the
      exception of the hinder half of the tarsus.

                                                              In. Lines.
 Length    from nose to root of tail                           28      0
           of tail                                             18      0


  Habitat, La Plata, (_July_.)


The La Plata Otter in its general colouring is of a somewhat deeper hue
than the European species, the cheeks and throat instead of being nearly
white are of a pale brown colour; the tail is longer in proportion, and
tapers more gradually; the tip of the muzzle is naked, but the hairless
portion is less than in that species, the boundary line between the
naked part and the hair of the top of the muzzle forming almost a
semicircle; the retiring extremities of this line touch the posterior
angle of the nostril on each side, whereas in the common otter the
boundary line of the hair of the muzzle is of a ｗ-like form. The skull
is figured in Plate 35, figs. 4, _a_, _b_, _c_, and _d_, and is compared
with that of _L. Chilensis_ in the next description.

“This specimen was killed by some fishermen a few miles from Maldonado,
near the mouth of the estuary of the Plata, where the water is quite
salt. I am not, however, by any means sure that it may not be a
fresh-water species, which had wandered from its proper station; in the
same manner as not unfrequently is the case with the _Hydrochærus
Capybara_. I am indebted to Mr. Chaffers, the master of the Beagle, for
having kindly presented me with this specimen.”—D.


                          2. LUTRA CHILENSIS.

  Lutra Chilensis, _Bennett_, Proceedings of the Committee of Science
  and Correspondence of the Zoological Society of London for 1832, p. 1.

  _L. fusca; vellere mediocri, laxo et sub-extante; mento, gulâ, et
    faciei lateribus, pallidè fuscis; pedibus saturatè fuscis; corporis
    pilis ad apicem pallidè fuscis; caudá mediocri; rostri apice calvo._

  DESCRIPTION.—This species scarcely equals a full grown European otter
      in size. It is of a brown colour throughout; the cheeks, chin, and
      throat, being slightly paler, and the feet of a deeper tint, than
      the other parts. The fur is moderately long, rather harsh to the
      touch, and semi-erect: the under fur is abundant, and of a soft
      and silk nature. The hairs of the ordinary fur are deep brown, but
      tipped with a very pale brown colour. The hairs of the tail, like
      those of the body, are harsh and semi-erect; towards the apex,
      those on the upper and under part are in a slight degree shorter
      than those at the sides, and lie closer to the skin; these
      differences, however, are not very apparent on the upper side,
      though distinct on the under. The feet are naked beneath, with the
      exception of the posterior half of the tarsus. The hair of the
      muzzle extends only down to the posterior angle of the nostrils,
      where it terminates in a straight line, leaving the tip of the
      muzzle naked.

                                                              In. Lines.
 Length    from nose to root of tail                           31      0
           of tail                                             14      3


  Habitat, Chonos Archipelago, (_January._.)


The Chile Otter was originally described by Mr. Bennett from a specimen
presented to the Zoological Society by Mr. Cuming, but as this specimen
is a young animal, scarcely half-grown, it does not present some of the
characters of the species in so marked a manner as the adult. I have,
therefore, availed myself of an adult specimen in Mr. Darwin’s
collection, to draw up the above description.

Compared with the Common Otter (_Lutra vulgaris_, Auct.) the most
striking difference consists in the character of the fur: the hairs
instead of being adpressed as in that species, are here semi-erect, and
appear as if they had been clipped at the extremity. The fur is of a
deeper colour, but has a slightly grizzled appearance, owing to the tip
of each hair being of a much paler colour than the remaining part.

In the young animal described by Mr. Bennett, (which in weight was
probably not more than one-third of that of the present animal) the
hairs of the body are of an uniform deep brown colour; hence, if I am
right in considering Mr. Darwin’s animal as the same species, it would
appear that the grizzled character of the fur is dependent on age.

The semi-erect fur will also serve to distinguish the present species
from the _Lutra Platensis_; the fur is likewise longer, the tail is
shorter, and the feet are smaller in proportion. The most important
distinctions, however, are furnished by the skulls; I will, therefore,
compare them.

The skull of _L. Chilensis_ compared with that of _L. Platensis_, (Plate
35, figs. 4.) when viewed from above, presents but little difference in
general form; it is, however, smaller in all its proportions, and the
zygomatic arch is a little less convex: the palate is proportionately
shorter; the tympanic bullæ are much smaller, less elevated, and wider
apart, in which respect there is a greater approximation to the skull of
_L. vulgaris_ than to that of _L. Platensis_; but here, the tympanic
bullæ are larger than in _L. Chilensis_. Both in _L. Chilensis_ and
_Platensis_, the sub-orbital foramina are kidney-shaped, the emarginated
portion being downwards, whilst in _L. vulgaris_ they approach somewhat
to a triangular figure, the apex being external. In _L. Chilensis_,
however, this foramen is comparatively larger than in _L. Platensis_,
and the outer portion of the foramen forms the segment of a larger
circle than the inner one, whilst in _L. Platensis_ both portions are
equal.

The principal difference in the dentition of the La Plata and the Chile
otters, consists in the comparatively smaller size of the posterior
molars, both of the upper and lower jaws, of the latter species. In the
upper jaw, the “carnassière” has its inner lobe, approaching somewhat to
a triangular form, whereas in _L. Platensis_ it is broader and almost
semicircular. In the lower jaw, the last molar but one has the inner
lobe much smaller than the middle outer lobe, whilst in _L. Platensis_
these two lobes are of nearly equal size and elevation. Other points of
dissimilarity will be perceived in the annexed table of admeasurements.

                                                     _L.         _L.
                                                 Chilensis._ Platensis._
                                                 In.  Lines.  In. Lines.
 Whole length of skull                             3      9¾    4     2½
 Greatest width                                    2      6⅓    2    10⅓
 Width of skull from the apex of one mastoid
   process to the opposite                         2      3¼    2     8¼
 Length of palate                                  1       6    1     10
 Breadth of palate between the posterior molars           7¾          7¾
 Length from last molar to posterior margin of
          palate                                          3⅓          5½
        from base of canine to hinder part of
          last molar                                     11⅔    1     1⅓
        of carnassière                                     5          5⅔
 Width of do.                                              5          6¼
 Length of last molar                                     2¾          3½
 Width of do.                                             4⅓          5⅔
 Length of ramus of lower jaw                      2      4½    2     8¾
        from canine to hinder portion of last
          molar (lower jaw)                        1      2¼    1     4¼
        of last molar but one (lower jaw)                 5¾          6⅔
 Width of do.                                             2⅔          3½

“These animals are exceedingly common amongst the innumerable channels
and bays, which form the Chonos Archipelago. They may generally be seen
quietly swimming, with their heads just out of water, amidst the great
entangled beds of kelp, which abound on this coast. They burrow in the
ground, within the forest, just above the rocky shore, and I was told,
that they sometimes roam about the woods. This otter does not, by any
means, live exclusively on fish. One was shot whilst running to its hole
with a large volute-shell in its mouth; another (I believe the same
species) was seen in Tierra del Fuego devouring a cuttle fish. But in
the Chonos Archipelago, perhaps the chief food of this animal, as well
as of the immense herds of great seals, and flocks of terns and
cormorants, is a red coloured crab (belonging to the family _Macrouri_)
of the size of a prawn, which swims near the surface in such dense
bodies, that the water appears of a red colour. This specimen weighed
nine pounds and a half.”—D.




                           FAMILY-DELPHINIDÆ.


                          DELPHINUS FITZ-ROYI.
                                PLATE X.

  _D. suprà niger; capitis corporisque lateribus, corporeque subtùs
    niveis; caudâ, pedibus, labioque inferiore, nigris; fasciis
    latis duabus per latus utrumque obliquè excurrentibus,
    nigréscenti-cinereis, hujusque coloris fasciâ, utrinque ab
    angulo oris ad pedem tendente._

  DESCRIPTION.—Upper parts of the body black, under parts pure white,
      the two blended into each other by gray: extremity of snout, a
      ring round the eye, the edge of the under lip, and the tail fin,
      black; dorsal and pectoral fins dark gray; a broad gray mark
      extends from the angle of the mouth to the pectoral fin; above
      which, the white runs through the eye and is blended into gray
      over the eye; two broad deep gray bands are extended in an oblique
      manner along each side of the body, running from the back
      downwards and backwards; iris of eye dark brown. Body anteriorly
      somewhat depressed, posteriorly compressed; head conical, arched
      above; the lower lip projecting beyond the upper; eye placed above
      and behind, but near the angle of the mouth; breathing vent
      situated in the same line as the eyes—supposing a circle to be
      taken round the head. Teeth slightly curved, and conical; in the
      upper jaw twenty-eight in number on each side, and in the lower,
      twenty-seven.

                                                         Ft.  In. Lines.
 Total length (measuring along the curve of back)          5    4      0
 Length       from tip of
                muzzle     to vent                         3   10      9
                           to dorsal fin                   2    6      5
                           to pectoral                     1    4      5
                           to eye                          0    9      9
                           to breathing aperture
                             (following curve of head)     0   10      7
                           to angle of mouth               0    7      9
              of dorsal fin along the anterior margin      1    0      5
 Height of do.                                             0    6      4
 Length of pectoral, along anterior margin                 1    2      8
 Width of tail                                             1    4      5
 Girth of
   body       before dorsal fin                            3    0      6
              before pectoral fin                          2    8      2
              before tail fin                              0    7      8
      of head over the eyes                                2    0      0


  Habitat, coast of Patagonia, Lat. 42° 30′, (_April_.)


This species, which I have taken the liberty of naming after Captain
FitzRoy, the Commander of the Beagle, approaches in some respects to the
_Delphinus superciliosus_ of the “Voyage de la Coquille,” but that
animal does not possess the oblique dark-gray bands on the sides of the
body; it likewise wants the gray mark which extends from the angle of
the mouth to the pectoral fins. In the figure the under lip of the _D.
superciliosus_ is represented as almost white, whereas in the present
species it is black: judging from the figures, there is likewise
considerable difference in the form. The figure which illustrates this
description agrees with the dimensions, which were carefully taken by
Mr. Darwin immediately after the animal was captured, and hence is
correct.

“This porpoise, which was a female, was harpooned from the Beagle in the
Bay of St. Joseph, out of several, in a large troop, which were sporting
round the ship. I am indebted to Captain FitzRoy for having made an
excellent coloured drawing of it, when fresh killed, from which the
accompanying lithograph has been taken.”—D.




                            FAMILY—CAMELIDÆ.


                      AUCHENIA LLAMA. _Desmarest._

  Guanaco of the aborigines of Chile.

“The Guanaco abounds over the whole of the temperate parts of South
America, from the wooded islands of Tierra del Fuego, through Patagonia,
the hilly parts of La Plata, Chile, even to the Cordillera of Peru. I
saw several of these animals in Navarin Island, forty miles north of
Cape Horn; the Guanaco, therefore, has, with the exception of a fox and
mouse, inhabitants of the same island, the most southern range of all
American quadrupeds. Although preferring an elevated site, it yields in
this respect to its near relative the Vicuña. On the plains of Southern
Patagonia, we saw them in greater numbers than in any other part.
Generally they go in small herds, from half a dozen to thirty together;
but on the banks of the Santa Cruz, we saw one herd, which must have
contained at least five hundred. On the northern shores of the Strait of
Magellan they are also very numerous. The Guanacoes are generally wild
and extremely wary: Mr. Stokes told me, that he one day in Patagonia saw
through a glass a herd of these beasts, which evidently had been
frightened, and were running away at full speed, although their distance
was so great that they could not be distinguished by the naked eye.

“The sportsman frequently receives the first intimation of their
presence, by hearing from a long distance their peculiar shrill neighing
note of alarm. If he then looks attentively, he will, perhaps, see the
herd standing in a line on the side of some distant hill. On
approaching, a few more squeals are given, and then off they set, at an
apparently slow but really quick canter, along some narrow beaten track
to a neighbouring hill. If, however, by chance he should abruptly meet a
single animal, or several together, they will generally stand
motionless, and intently gaze at him;—then, perhaps, move on a few
yards, turn round, and look again. What is the cause of this difference
in their shiness? Do they mistake a man in the distance for their chief
enemy the puma? Or does curiosity overcome their timidity? That they are
curious is certain, for if a person lies on the ground, and plays
strange antics, such as throwing up his feet in the air, they will
almost always approach by degrees to reconnoitre him. It is an artifice
that was repeatedly practised with success by the sportsman of the
Beagle, and it had moreover the advantage of allowing several shots to
be fired, which were all taken as parts of the performance. On the
mountains of Tierra del Fuego, and in other places, I have more than
once seen a Guanaco on being approached, not only neigh and squeal, but
prance and leap about in the most ridiculous manner, apparently in
defiance, as a challenge. These animals are very easily domesticated,
and I have seen some in this state near the houses in northern
Patagonia, although at large on their native plains. They are, when thus
kept, very bold, and readily attack a man, by striking him from behind
with both knees. It is asserted, that the motive for these attacks is
jealousy on account of their females. The wild Guanacoes, however, have
no idea of defence; and even a single dog will secure one of these large
animals, till the huntsman can come up. In many of their habits they are
like sheep in a flock. Thus when they see men approaching in several
directions on horseback, they soon become bewildered, and know not which
way to run. This circumstance greatly facilitates the Indian method of
hunting, for they are thus easily driven to a central point, and are
encompassed.

“The Guanacoes readily take to the water; several times at Port Valdes
they were seen swimming from island to island. Byron, in his voyage,
says he saw them drinking salt water. Some of our officers likewise saw
a herd apparently drinking the briny fluid from a Salina near Cape
Blanco; and in several parts of the country, if they do not drink salt
water, I believe they drink none at all. In the middle of the day, they
frequently roll in the dust, in saucer-shaped hollows. The males often
fight together; one day two passed quite close to me, squealing and
trying to bite each other; and several were shot with their hides deeply
scored. Herds appear sometimes to set out on exploring parties: at Bahia
Blanca, where within thirty miles of the coast these animals are
extremely scarce, I one day saw the tracks of thirty or forty, which had
come in a direct line to a muddy salt water creek. They then must have
perceived, that they were approaching the sea, for they had wheeled with
the regularity of cavalry, and had returned back in as straight a line,
as they had advanced. The Guanacoes have one singular habit, the motive
of which is to me quite inexplicable, namely, that on successive days
they drop their dung on one defined heap. I saw one of these heaps,
which was eight feet in diameter, and necessarily was composed of a
large quantity. Frezier remarks on this habit as common to the Guanaco
as well as to the Llama;[13] he says it is very useful to the Indians,
who use the dung for fuel, and are thus saved the trouble of collecting
it.

“The Guanacoes appear to have favourite spots for dying in. On the banks
of the Santa Cruz, the ground was actually white with bones in certain
circumscribed spaces, which generally were bushy and all near the river.
On one such spot I counted between ten and twenty heads. I particularly
examined the bones; they did not appear, as some scattered ones which I
had seen, gnawed or broken as if dragged together by a beast of prey.
The animals in most cases, must have crawled, before dying, beneath and
amongst the bushes. Mr. Bynoe informs me, that during the last voyage,
he observed the same circumstances on the banks of the Rio Gallegos. I
do not at all understand the reason of this; but I may add, that the
Guanacoes which were wounded on the plains near the Santa Cruz
invariably walked towards the river. This quadruped seems particularly
liable to contain in its stomach bezoar stones. The Indians who trade at
the Rio Negro, bring great numbers to sell as Remedios or quack
medicines; and I saw one old man with a box quite full of them, large
and small.”—D.




                            FAMILY-CERVIDÆ.


                           CERVUS CAMPESTRIS.

  Cervus campestris, _F. Cuvier_, in Dict. des Sc. Nat. VII. p. 484.

  ——, Cuvier Oss. Foss. IV. p. 51. Pl. 3. f. 46.[14]

  Guazuti, _Azara_, “Natural History of the Quadrupeds of Paraguay.” W.
  P. Hunter’s translation, vol. i. p. 135.

  ——, French translation, vol. i. p. 77.

Besides skins of this species of stag, I find, in Mr. Darwin’s
collection, three pairs of horns, which, together with a pair belonging
to one of the skins, constitute a sufficiently complete series to
illustrate the different forms which these appendages assume, as the
animal increases in size.

[Illustration]

The above four sketches, which are all drawn to the same scale, will
help to convey a clear idea of the forms, and relative proportions, of
these horns.

The most simple horn (fig. 1.) consists of a _beam_, eight and a half
inches long, which is slightly arched outwards and considerably
compressed about two and a half inches from the apex. At one inch from
the base there is a small brow antler which projects forwards and
upwards.

In the next horn, (fig. 2.) there is the same small brow antler, but
there is a single small _snag_, about equal in size to the brow antler,
which is directed backwards and upwards, and is situated at three and a
quarter inches from the apex of the beam. The total length of the beam
is eight inches, measured in a straight line.

The third pair of horns, (fig. 3.) which must have belonged to an animal
considerably older than either of the preceding pairs, exhibits a large
brow antler, in length exceeding half that of the beam: here the
posterior snag is also large, and is directed backwards and upwards,
whilst the apical portion of the beam is directed forward about as much
as the snag is directed backwards. The total length of this horn is
eleven and a half inches, measured in a straight line.

The last figure (No. 4.) represents the horn of one of the specimens of
which an entire skin was brought over. This horn differs only from the
last in being slightly larger, and in having two additional small snags,
one springing from the under side, and near the apex, of the brow
antler, and the other springing from the hinder part, and near the apex
of the great posterior snag.

“The Spaniards say they can distinguish how old a deer is by the number
of the branches on the horns. They affirmed that the specimen, of which
figure 4 represents one of the horns, was nine years old. It certainly
was a very old one, as all its teeth were decayed. This specimen was
killed at Maldonado, in the middle of June; another specimen was killed
at Bahia Blanca, (about three hundred and sixty miles southward,) in the
month of October, with the hairy skin on the horns: there were others,
however, whose horns were free from skin. At this time of the year, many
of the does had just kidded. I was informed, by the Spaniards, that this
deer sheds its horns every year.

“The _Cervus campestris_ is exceedingly abundant throughout the
countries bordering the Plata. It is found in Northern Patagonia as far
south as the Rio Negro, (Lat. 41°); but, further southward, none were
seen by the officers employed in surveying the coast. It appears to
prefer a hilly country; I saw very many small herds, containing from
five to seven animals each, near the Sierra Ventana, and among the hills
north of Maldonado. If a person, crawling close along the ground, slowly
advances towards a herd, the deer frequently approach, out of curiosity,
to reconnoitre him. I have by this means killed, from one spot, three
out of the same herd. Although thus so tame and inquisitive, yet, when
approached on horseback, they are exceedingly wary. In this country
nobody goes on foot, and the deer knows man as its enemy, only when he
is mounted, and armed with the bolas. At Bahia Blanca, a recent
establishment in Northern Patagonia, I was surprised to find how little
the deer cared for the noise of a gun: one day, I fired ten times, from
within eighty yards, at one animal, and it was much more startled at the
ball cutting up the ground, than at the report.

“The most curious fact, with respect to this animal, is the
overpoweringly strong and offensive odour which proceeds from the buck.
It is quite indescribable: several times, whilst skinning the specimen,
which is now mounted at the Zoological Museum, I was almost overcome by
nausea. I tied up the skin in a silk pocket-handkerchief, and so carried
it home: this handkerchief, after being well washed, I continually used,
and it was, of course, as repeatedly washed; yet every time, when first
unfolded, for a space of one year and seven months, I distinctly
perceived the odour. This appears an astonishing instance of the
permanence of some matter, which in its nature, nevertheless, must be
most subtile and volatile. Frequently, when passing at the distance of
half a mile to leeward of a herd, I have perceived the whole air tainted
with the effluvium. I believe the smell from the buck is most powerful
at the period when its horns are perfect, or free from the hairy skin.
When in this state the meat is, of course, quite uneatable; but the
Spaniards assert, that if buried for some time in fresh earth, the taint
is removed. These deer generally weigh about sixty or seventy
pounds.”—D.




                             FAMILY—MURIDÆ.


                           1. MUS DECUMANUS.
                       Mus decumanus, _Auctorum_.

In the extensive collection of Rodent animals brought home by Mr.
Darwin, I find several specimens of the above named species, that is to
say, animals which resemble the European specimens of _Mus Decumanus_ in
all those characters which are the least liable to variation in
individuals of the same species, such as the proportions which the
various parts of the animal bear to each other: they differ, however,
somewhat in colouring.

Buenos Ayres, Maldonado, Valparaiso, East Falkland Island, and Keeling
Island, are each, it appears, infested with the common European rat. I
have now before me two specimens from East Falkland Island, and one
specimen from each of the other localities, and among these I find none
equal in size to the largest European specimens: as regards the
colouring, the Buenos Ayres specimen differs only from the English
specimens of _Mus Decumanus_, in having the upper parts of a richer and
deeper hue, owing to the tips of the shorter hairs being of a deep
yellow instead of pale yellow, and in having a rusty tint over the
haunches.

Mr. Darwin found this variety “common about houses in the country around
Buenos Ayres.”

In the Maldonado variety, the shorter hairs of the upper parts of the
body are of a rusty yellow colour at the apex, in other respects it
resembles the British variety. The rusty yellow colour of the tips of
the hairs produces a general reddish hue, which is the more conspicuous,
when the animal is placed near an English specimen. “Was caught in a
house, at Maldonado. I saw a specimen of the common gray English, or
Norway rat, lying dead in the streets, and it certainly had a very
different appearance from these red rats. The latter, I saw crawling
about the hedges in the interior provinces at Santa Fé, and likewise in
the forest of the island of Chiloe. This latter fact, however, is a
strong argument against its being aboriginal, since I did not find even
one undoubted American species, out of the many which I collected,
inhabiting both sides of the Cordillera.”—D.

The specimen from Valparaiso very closely resembles that from Maldonado;
it is, perhaps, a little less red. “Common about the houses in the town
of Valparaiso.”

The two specimens from East Falkland are of a brighter hue, and have
less gray in their colouring, than in the European variety of the common
rat. “One of them was caught in a Bay, which is sometimes frequented by
shipping, but which is distant thirty or forty miles from any
habitation. These rats have spread, not only over the whole of East and
West Falkland, but even on some of the outlying islets. When the cold,
wet, and gloomy nature of the climate is considered, it is surprising
that these animals should be able to find food to live on.”—D.

The general hue of the Keeling Island specimen, is deep brown, the
longer hairs of the upper parts of the body being, as usual, black; but
the shorter hairs, instead of having the pale yellow tint which we
observe in the European, (or, rather, British) specimens of _Mus
Decumanus_, are of a deep, rusty yellow. The most remarkable difference,
however, consists in the colouring of the under parts being of a
yellowish tint, and, towards the root of the tail, of a very distinct
buff yellow: the feet are brownish.

“This rat is exceedingly numerous on some of the low coral islets
forming the margin of the Lagoon of Keeling Island, in the Indian Ocean.
The climate is dry and hot. The rats are known to have come in a vessel
from the Mauritius, which was wrecked on one of the islets, which is now
called Rat Island. They appeared stunted in their growth, and many of
them were mangy. They are supposed to live chiefly on cocoa-nuts, and
any animal matter the sea may chance to throw up. They have not any
fresh water; but the milk of the cocoa-nut would supply its place.”—D.

The principal dimensions of the above animals are as follows:—

                                   Specimen
                                     from
                                    Buenos
                                    Ayres    Maldonado. Valparaiso.
                                  In. Lines. In. Lines.  In. Lines.
 Length from nose to root of tail   9      9   9      3    8      6
        of tail                   Imperfect    6      0    6      6
        of tarsus                   1      7   1      7    1      7

                                      East       East     Keeling
                                   Falkland.  Falkland.   Island.
                                   In. Lines. In. Lines. In. Lines.
 Length from nose to root of tail    8      9   9      0   8      3
        of tail                    Imperfect    6      0   6      6
        of tarsus                    1      7   1      7   1      7

Upon comparing the skull of the Valparaiso variety with that of a
British specimen of _Mus decumanus_, I could perceive no difference. A
skull from West Falkland did not differ, neither did the dentition of
the Keeling Island specimen above noticed. A perfect specimen of this
last I have not had an opportunity of examining.


                  2. MUS (DECUMANUS _var._ ?) MAURUS.

  Mus maurus, _Waterh._ in Proceedings of the Zoological Society of
  London, for February, 1837, p. 20.

  _M. pilis suprà purpurescenti-nigris; subtùs plumbeis; auribus
    parvulis, pallidè fuscis: caudâ corpus ferè æquante._

  DESCRIPTION.—The character of the fur of this animal nearly resembles
      that of _Mus decumanus_; it is, however, of a harsher nature: the
      general colour of the upper parts and sides of the body is
      purple-black, arising from the longest hairs being of this colour,
      and likewise the tips of those which are next in length; the
      latter, however, excepting at the tip, are white, and this white
      is not entirely hidden, even when the hairs are in their ordinary
      position: on the head the hairs assume a brownish hue, and are
      tolerably uniform: the limbs, and under parts of the body, are of
      a deep gray colour, with a faint purple-brown wash: the under fur
      is gray: the ears are small, of a brown-white, or very pale brown
      colour, and furnished with minute brown hairs: the small,
      scattered, bristly hairs of the tail are of an uniform brownish
      black colour. The hairs of the moustaches are black at the base,
      and grayish at the apex.

                                                              In. Lines.
 Length    from nose to root of tail                           11      3
           of tail                                              7      6
           of tarsus                                            1      8
           of ear                                               0     6¼
           from nose to ear                                     2      2


  Habitat, Maldonado, La Plata, (_June_.)


This rat is very closely allied to _Mus decumanus_, and I think may
possibly prove an extraordinary local variety of that animal. Having but
one skin, and no skull, I am unable to satisfy myself on this point. Its
size, as will be seen by the admeasurements, exceeds that of the common
rat, or, rather, it exceeds ordinary specimens of that animal, for I
have seen _some_ which were equal to it.

“It was killed near Maldonado, where it frequented holes in the sand
hillocks near the shore. It is likewise found on the island of Guritti.
If ships are ever infested with these monstrous rats, the
above-mentioned localities are very likely places to have received
colonies by such means. An old male weighed fifteen ounces and three
quarters. The ears of this rat, when alive, were of a pale colour, which
made a singular contrast with the black fur of its body.”—D.


                            3. MUS JACOBIÆ.

  Mus decumanoïdes,[15] _Waterh._ in “Catalogue of the Mammalia
  preserved in the Museum of the Zoological Society of London.”

  _M. suprà fuscus, griseo-lavatus, subtùs albus: pedum pilis sordidè
    albis; caudâ corpore cum capite paulò longiore; auribus mediocribus:
    pilis perlongis in dorso crebrè inter cæteros commixtis._

  DESCRIPTION.—The general tint of the upper parts of this rat, is
      grayish brown, (very nearly resembling that of _Mus decumanus_);
      the longest hairs, which on the hinder portion of the back are one
      inch and a half in length, are black; the ordinary hairs are black
      at the apex, there is then, on each hair, a considerable space
      occupied by pale yellow, and the remaining, or basal portion, is
      grayish white; the under fur is gray: the hairs of the chin,
      throat, and under parts of the body, are white, and without any
      gray colour at the roots: the feet are covered with dirty grayish
      hairs: the tail, which is slender, is very sparingly furnished
      with minute black hairs, both above and beneath: the ears are of
      moderate size, of a brownish flesh-colour, and, to the naked eye,
      appear to be destitute of hair. The hairs of the moustaches are
      most of them black at the base, and grayish at the apex.

                                                              In. Lines.
 Length    from nose to root of tail                            7      6
           of tail                                              7      6
           of tarsus                                            1     4¼
           of ear                                               0     7½
           from nose to ear                                     1     7½


  Habitat, James Island, Galapagos Archipelago, Pacific Ocean,
  (_October_.)


This species is scarcely equal in size to a full grown common black rat,
(_Mus Rattus_), the head is rather shorter in proportion, the tarsi are
smaller, and the tail is longer. In the character of the fur, and length
of the hairs, it _very_ closely resembles that species: the ears are
larger than in _M. decumanus_, and about equal to those of _M. Rattus_.
In having the hairs of the under parts of the body of an uniform colour,
(i. e. not gray at the base,) it resembles the _Mus Tectorum_ of Savi;
but the large size of that animal, the greater length of the fur, and
its colouring, all serve to distinguish it from the present species,
which I may here observe, is truly an old world form, and very distinct
from another species, also from the Galapagos, which is hereafter
described.

“It is very common in James Island, but is not found on all the islands,
if on any other in the Archipelago. Although its appearance is so like
that of the common rat, yet its habits appear to be rather different: it
is less carnivorous, and does not appear to be so strongly attached to
the habitations of man. This island was frequented, about one hundred
and fifty years since, by the vessels belonging to the Bucaniers; so
that the common rat might easily have been transported here. And if a
very peculiar climate, a volcanic soil, and strange food, can together
produce a race, or strongly marked variety, there is every probability
of such change having taken place in this case.”—D.


                   4. MUS (RATTUS _var._?) INSULARIS.

  _M. suprà grisescenti, colore subtùs dilutiore; tarsis
    purpureo-nigris: caudâ corpus cum capite æquante: auribus
    mediocribus: vellere molli._

  DESCRIPTION.—No. 1. The general colour of this animal is what might be
      termed black, there is, however, an obscure purple-brown hue on
      the upper parts of the body, and the sides and under parts have a
      grayish tint, the hairs covering the feet above are of an uniform
      deep purple-brown, almost black. All the hairs of the body are
      gray at the base: the hairs of the moustaches are long and
      numerous, and of a black colour, having one or two white hairs
      intermixed: the ears are of moderate size, and very sparingly
      furnished with minute dark hairs: the tail is long and slender,
      and has small, scattered, bristly hairs, of a brown-black colour.

                                                              In. Lines.
 Length    from nose to root of tail                            7      0
           of tail                                              6      6
           of tarsus                                            1     3½
           of ear                                               0      7
           from nose to ear                                     1      6

  No. 2. Hairs along the centre of the back chiefly black, and but
      obscurely annulated, near the apex, with deep yellow: towards the
      sides of the body, and over the haunches, the hairs are more
      distinctly annulated, and on the sides of the body they are of a
      pale yellow at the apex: on the under parts the hairs are gray,
      tipped with dirty yellowish white: the feet are of the same deep
      purple-brown hue as in the specimen first described.

  Habitat, Ascension Island, Atlantic Ocean, (_July_.)

These two animals not only differ in the colour of the fur, one being of
a grizzled brownish colour, and the other black, but there is a
considerable difference in the texture of the fur. In the black
specimen, the fur is very soft and glossy, and the long hairs, which are
abundant, are very slender. In the brown specimen, the fur is of a
harsher nature, the long hairs are not so abundant, but longer, and less
slender. On the other hand, they agree in size, dentition, the length of
the head, tarsus, and ears, and differ but in a trifling degree (about
three lines,) in the length of the tail.

Upon comparing the Ascension Island specimens with _M. Rattus_, I find
that, although in size they are about one-third less, yet the teeth
precisely agree, not only in form, but in size. The relative proportions
of the head, ears, and tarsi, also agree. Besides the general colouring
of the fur, they both differ in having the hairs of the feet uniformly
purple-black, those in _Mus Rattus_ being much paler, and even whitish,
on the toes. In the character of the fur, there is much difference. The
long silky hairs, which are so conspicuous in _Mus Rattus_, are
replaced, in the black specimen, by hairs which are scarcely to be
distinguished from the ordinary fur; and in the other specimen, although
rather longer and more distinct, they are short, compared with those of
the black rat.

“The specimen which has a black, and glossy fur, frequents the short
coarse grass near the summit of the island, where the common mouse
likewise occurs. It is often seen running about by day, and was found in
numbers, when the island was first colonized by the English, a few years
since. The other, and browner coloured variety, lives in the out-houses
near the sea-beach, and feeds chiefly on the offal of the turtles,
slaughtered for the daily food of the inhabitants. If the settlement
were destroyed, I feel no doubt that this latter variety would be
compelled to migrate from the coast. Did it originally descend from the
summit? and, in the case just supposed, would it retreat there? and, if
so, would its black colour return? It must, however, be observed, that
the two localities are separated from each other by a space, some miles
in width, of bare lava and ashes. Does the summit of Ascension, an
island so immensely remote from any continent, and the summit itself
surrounded by a broad fringe of desert volcanic soil, possess a small
quadruped, peculiar to itself? Or, more probably, has this new species
been brought, by some ship, from some unknown quarter of the world? Or,
I am again tempted to ask, as I did in the case of the Galapagos rat,
has the common English species been changed, by its new habitation, into
a strongly marked variety?”—D.

Mr. Darwin seems to have foreseen the difficult problem which these two
rats have furnished, and although I have spent much time in studying the
Muridæ, I must confess I have been exceedingly puzzled by the animals in
question. It appears as if the brown, and black rats, (_M. decumanus_,
and _M. Rattus_,) and likewise the common mouse, (_M. Musculus_,)[16]
all of which follow man in his peregrinations, and which, to a certain
degree, are dependent upon man, and may therefore be termed
semi-domestic animals; like _really_ domestic animals, are subject to a
greater degree of variation than those species which hold themselves
aloof from him.

Upon the whole then I have determined to describe the two Ascension
Island specimens as one species, and as varieties of the _Mus Rattus_,
but with a mark of doubt, since I do not possess sufficient materials
for a rigorous examination, having, in fact, but one skin of each
variety, and neither skull nor skeleton. I have also applied the name of
_insularis_, to designate this variety or species, whichever it may be,
for, supposing it be not a distinct species, it is so marked a variety,
that a name for it is desirable.


                            5. MUS MUSCULUS.

  Mus Musculus, _Auctorum_.

Of this species, there are six specimens in Mr. Darwin’s collection; two
were found “living in the short grass, near the summit of the Island of
Ascension, where the climate is temperate.”—D. Two others were procured
“on a small, stony, and arid island, near Porto Praya, the capital of
St. Jago, in the Cape de Verde Islands,—climate very hot and dry.
Excepting during the rainy season, which is of short duration, these
little animals can never taste fresh water, nor does the island afford
any succulent plant.”—D. A specimen was also procured “on a grassy
cliff, on East Falkland Island, at the distance of a mile from any
habitation. It is singular that so delicate an animal should be able to
subsist under the cold, and extremely humid climate, of the Falkland
Islands, and on its unproductive soil.”—D. These specimens are all of
them rather less than full grown individuals of the same species
procured in England; in other respects, they do not differ.

The sixth specimen, which is from Maldonado, is considerably less than
British specimens of the common mouse, and is of a richer and brighter
colour, the head is smaller, the muzzle shorter in proportion, whilst
the tarsi are even longer than in a large specimen of _M. Musculus_.
These points of dissimilarity induced me to believe it was a distinct
species, and to apply to it the specific name of _brevirostris_.[17]
Upon re-examination, with the advantage of more experience, and
consequently a better knowledge of the characters of these animals, I
have changed my opinion. The teeth indicate that it is not an adult
specimen, and agree perfectly with those of _M. Musculus_, both in form
and size. “Common in the houses of the town of Maldonado, and its habits
are similar to those of _Mus Musculus_.”—D.


                         6. MUS LONGICAUDATUS.
                               PLATE XI.

  Mus longicaudatus, _Bennett_, Proceedings of the Committee of Science
  and Correspondence of the Zoological Society of London for January,
  1832, p. 2.

  _M. pallidè flavescenti-fuscus; corpore subtùs albo, levitèr flavo
    lavato; pedibus albis; tarsis permagnis; caudâ perlongâ; auribus
    parvulis._

  DESCRIPTION.—Fur long and soft; general colour pale yellow-brown, the
      hairs of the ordinary fur being fulvous near the apex, and the
      longer hairs brown. On the sides of the body, cheeks, and external
      side of limbs, the fulvous hue prevails. The inner side of the
      limbs and the under parts of the body are white, but have an
      indistinct yellowish hue. All the hairs of the body are of a deep
      gray colour at the base. The ears are small, well clothed with
      hairs; those on the inner side are chiefly yellow; externally, on
      the fore part they are brown, and posteriorly whitish. The feet
      are of a flesh-colour, and furnished above with white hairs; the
      tarsi are but sparingly provided with minute hairs on the upper
      side, and are naked beneath: they are of unusually large size. The
      fore feet are of moderate[18] size, and furnished with a very
      large carpal tubercle. The tail is very nearly double the length
      of the body, if the latter be measured in a straight line; it is
      of a brownish flesh-colour above, paler beneath, and sparingly
      furnished with minute bristly hairs; those on the upper surface
      being brown, and on the under side white. The hairs of the
      moustaches are long, of a black colour, and grayish at the apex.

                                                              In. Lines.
 Length    from nose to root of tail                            3      9
           of tail                                              5      3
           from nose to ear                                     0    10½
           of tarsus (claws included)                           1      1
           of ear                                               0      4


  Habitat, Chile.


The most conspicuous characters of the present species consist in the
immense length of the tail, and the great size of the hinder feet.[19]
It is about equal in size to _Mus Musculus_; its form, however, is
somewhat stouter; in colour it is much paler and brighter. The head is
larger in proportion; the ears are smaller, and more densely clothed
with hair; the fore feet are rather larger, and the fleshy tubercle on
the under side of the wrist is also larger. The thumb nail is flattened,
and rounded at the tip, as in _Mus Musculus_, but is longer, and more
distinct than in that animal.

The skull of _M. longicaudatus_, (Plate 34, Fig. 1,) is considerably
larger than that of the common mouse, but in form scarcely differs from
it; its upper surface is rather more convex, and the interparietal bone
proportionately less. The length of the skull is 1 inch; breadth, 6½
lines; distance between the forepart of the incisor, and the first molar
of the upper jaw, 3½ lines. The dentition is figured in Plate 34, Figs.
1. _b_ and 1. _c_.

The above account is drawn up from the same specimen as that from which
Mr. Bennett took his description, and which was brought from Chile by
Mr. Cuming, who states that the animal in question lives in trees, and
constructs its nest with grass.

In Mr. Darwin’s collection, I find an animal which agrees in all the
more important characters with the one above described, but differs in
being of a deeper colour, (approaching more nearly, in this respect, to
the common mouse,) and in having the tail a trifle shorter. The skull is
about ¾ of a line shorter, but its proportions agree precisely: the
proportions of the feet, and the general form of the animal, also agree.
This specimen is likewise from Chile, (Lat 37° 40′,) and, according to
Mr. Darwin, “overran the wooded country south of Concepcion, in swarms
of infinite numbers. Captain FitzRoy, on his return from visiting the
wreck of H. M. S. Challenger, had the kindness to bring me this
specimen. So destructive was this little animal, that it even gnawed
through the paper of the cartridges belonging to the people who were
wrecked.”—D.


                              MUS ELEGANS.
                               PLATE XII.

  Mus elegans, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 19.

  Eligmodontia typus, _F. Cuvier_, Annales des Sciences Naturelles for
  March 1837. Tom. 7. p. 169. Pl. 5.

  _M. suprà flavus, vellere pilis fuscescentibus adsperso, his ad
    latera, et prope oculos rarioribus; pilis pone aurem utramque,
    labiis, corpore subtùs, pedibusque niveis; auribus magnis; caudâ
    capite corporeque paulo longiore; tarsis longis subtùs pilis
    obsitis._

  DESCRIPTION.—Fur very long and soft; general colour of the upper parts
      of the body pale brownish yellow; the lower portion of the cheeks,
      and the under parts of the body pure white: the hairs of the
      ordinary fur of the back are gray at the base, pale ochre near the
      apex, and brown at the apex; the longer hairs are brownish. On the
      sides of the body where the longer hairs are less numerous, the
      pale ochre colour prevails; the hairs on this part as on the back
      are deep gray at the base, but at a short distance from the apex
      they are white; nearer the tip shaded into yellow, and at the tip
      brownish: the limbs externally are of a pale yellow colour. The
      hairs of the throat and chest are pure white to the root, those on
      the belly are obscurely tinted with gray at the root. The feet are
      of a pale flesh-colour, and furnished with white hairs; the fore
      feet are of moderate size; the thumb nail is small and rounded,
      and the carpal tubercle is covered with hairs; the tarsi are long,
      and the white hairs extend over the whole of the under parts; the
      under side of the toes, however, are but sparingly furnished.
      There appears to be but one large tubercle on the under side of
      the tarsus, and this, which is situated near the base of the toes,
      is thickly covered with silvery-white hairs. The tail is long,
      pale brown above, and pale flesh-colour beneath; above, it is
      furnished with minute brown hairs, and on the under side with
      white hairs. The ears are rather large, of a pale flesh-colour,
      tolerably well clothed with hairs, which are of a pale yellow
      colour on the inner side, and white on the outer side—excepting on
      the fore part, where they are brown. A small tuft of white hairs
      springs from the base of the ear posteriorly. The hairs of the
      moustaches are moderate; black at the base, and grayish at the
      apex.

                                                              In. Lines.
 Length    from nose to root of tail                            3      7
           of tail                                              3      9
           from nose to ear                                     1      0
           of tarsus                                            0     10
           of ear                                               0      6


  Habitat, Bahia Blanca, (_September_.)


Upon comparing the skull (Pl. 34, fig. 2, _a._) of _M. elegans_ with
that of _M. Musculus_, the most evident points of distinction consist in
the greater proportionate length of the nasal and frontal bones, and the
slenderness of the zygomatic arch in the former animal. Length of skull
11 lines, width 6 lines, distance between front molar and outer side of
incisors of upper jaw 3⅜ lines, length of nasal bones 4⅜ lines.

The dentition is figured in Pl. 34, figs. 2. _b_, and 2. _c_.

“Whilst bivouacking one night on shore, amongst some sand hillocks, this
mouse, with its tail singed, leapt out of a bush which was placed on the
fire. Its hind legs appeared long in proportion to the front, and it did
not appear to be very active in endeavouring to make its escape.”—D.

_Mus elegans_ is about equal in size to _M. Musculus_; the head is
larger in proportion than in the latter, the ears are slightly larger,
the tail is longer, and so are the tarsi. The large ears, long tail, and
comparatively large size of the feet, combined with the greater size of
the animal itself, will render it easy to distinguish this species from
_M. gracilipes_ and _M. bimaculatus_. From the last mentioned animal it
moreover differs in having the head larger in proportion, the fur
longer, and the colouring of the upper parts of the body somewhat
darker. The white fur is almost confined to the under parts of the body,
and there is but a small tuft of white hairs behind the ears, whereas in
_M. bimaculatus_, the white fur extends considerably on the sides of the
body, the outer side of the limbs are white, and there is a large and
conspicuous white spot behind each ear.

In _M. elegans_ the whole sole of the tarsus and the carpal tubercles
are covered with hair. In _Mus bimaculatus_ the hinder _half_ of the
tarsus only is covered with hair, and in _M. gracilipes_ both the hinder
half is covered, and there are some scattered hairs extending almost to
the two tubercles, which are situated at the base of the longer toes.

The genus _Eligmodontia_ of M. F. Cuvier, founded upon a species of
mouse from Buenos Ayres, possesses nearly the same characters as the
subgenus _Calomys_, established by me in the Proceedings of the
Zoological Society for February 1837, and which included the animal
above described, and two other species (_M. bimaculatus_ and _M.
gracilipes_). M. Cuvier’s genus is distinguished by there being only one
large tubercle on the under side of the tarsus, and in having the carpal
pad covered with hair as well as the pad of the tarsus. In these
characters our present animal agrees, as it does also in size and in the
relative proportions of the tail and tarsus, circumstances which induce
me to believe they are identical.

In _M. bimaculatus_ and _M. gracilipes_ there are six naked tubercles on
the under side of the tarsus, and the carpal pad is also naked. In
having, however, the tarsus hairy beneath,[20] in dentition and in
colouring, they agree so closely with _M. elegans_ that I think they
cannot be separated generically.


                            MUS BIMACULATUS.
                               PLATE XII.

  Mus bimaculatus, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 18.

  _M. vellere pallidè ochraceo, pilis nigricantibus adsperso, his ad
    latera rarioribus; rostri lateribus, notá magná pone aurem utramque,
    artubus, corporeque subtùs niveis; auribus mediocribus; caudâ, quoad
    longitudinem, corpus fere æquante; tarsis ad calcem pilis
    argenteo-candidis obsitis._

  DESCRIPTION.—Upper parts of the body of a very pale ochre colour, the
      longer hairs, however, are black, and at the apex grayish, and
      where they are numerous, as on the back and upper surface of the
      head, they give greater depth to the colouring; the cheeks and
      sides of the body are of an almost uniform pale, but bright
      yellow; the sides of the muzzle, the lower half of the cheeks, the
      lower portion also of the sides of the body, and the whole of the
      under parts, are pure white—each hair being uniform in colour to
      the root, and not, as is usually the case, _gray_ at the root.
      There is likewise a large patch of pure white hairs behind each
      ear. The feet and tail are of a pale flesh-colour, and furnished
      with white hairs, with the exception of those on the upper surface
      of the latter, which are pale brown. The ears are also pale
      flesh-colour, clothed internally with yellow hairs; externally on
      the fore part, the hairs are brownish, and on the hinder part,
      white—they are rather large, and so are the feet. The tail is
      about equal to the body in length. The hairs of the moustaches are
      numerous and slender, and most of them are black at the base, and
      gray at the apex. The hinder half of the tarsus beneath is covered
      with minute silvery-white hairs; beside the ordinary tubercles,
      the anterior portion of the sole of the foot and the base of the
      toes beneath, are crowded with small rounded warts, which are much
      more numerous and conspicuous than in the common mouse.

                                                              In. Lines.
 Length    from nose to root of tail                            3      1
           of tail                                              1     11
           from nose to eye                                     0     4½
           from nose to base of ear                             0     8¾
           of tarsus (claws included)                           0      8
           of ear                                               0     4½


  Habitat, Maldonado, La Plata, (_June_.)


The skull of this animal, is rather shorter and broader than that of
_Mus Musculus_, the upper surface is more arched, the zygomatic arch is
much more slender, and the nasal bones are rather broader. In the
convexity of the upper surface, and the slenderness of the zygomatic
arch, this skull very nearly resembles that of _M. gracilipes_; this
latter, however, has the zygomatic arch more convex, projecting more
suddenly on the anterior part, and the interparietal bone smaller.
Length of skull 10 lines, width 5½, length of nasal bones 4 lines,
distance between the outer side of the incisors, of the upper jaw, and
the first molar 2⅞ lines. See Plate 34, fig. 3. _a_.

The dentition is figured in Plate 34, figs. 3. _b_ and _c_.

This mouse is rather less than _M. Musculus_, the tail is much shorter
in proportion, the fur is longer and softer, and the ears are more
distinctly clothed with hair.

The pale and delicate yellow colour of the upper parts of the body, and
the pure white of the under parts, renders the present species
conspicuous amongst its congeners. I may further remark that the white
colour which in the Muridæ (when it occurs) is usually confined to the
under part of the body, or extends but slightly on the sides, is in the
present animal extended considerably on the sides of the body, and
occupies an equal portion with the yellow of the upper parts. The name
_bimaculatus_ is applied to this animal on account of the two
conspicuous white patches, which are situated behind the ears.

In affinity as well as in appearance it most nearly approaches to _Mus
gracilipes_ and _M. elegans_; with no other species of the genus _Mus_,
here described, can it be confounded, since these only have the tarsus
hairy beneath.

The principal points of distinction between the present animal and _Mus
elegans_, are noticed in the account of that species.

“This mouse, when alive, had a very elegant appearance. A countryman,
who brought it me, found six of them living together in one burrow.”—D.


                            MUS GRACILIPES.
                               PLATE XI.

  Mus gracilipes, _Waterh._, Proceedings of the Zoological Society of
  London, for February 1837, p. 19.

  _M. suprà flavo-lavatus; pilis pone aurem utramque, labiis, corporeque
    subtùs, albis; pedibus parvulis, gracilibus, carneis, suprà et ad
    calcem pilis albis tectis; caudâ gracili, pilis albis instructâ,
    quoad longitudinem corpus ferè æquante; auribus mediocribus; vellere
    mediocri et molli, pilis omnibus ad basin plumbeis._

  DESCRIPTION.—General colour very pale yellowish brown, a tint produced
      by the admixture of black and pale fawn colour; the hairs of the
      ordinary fur being of the latter tint near the apex, and dusky at
      the apex, whilst the longer hairs are black. The feet, tail, under
      parts of the body and the sides of the muzzle, are pure white. All
      the hairs of the body, (which are soft, and of moderate length),
      are deep gray at the base. The ears are of moderate size, well
      clothed with hairs, of which those on the inner side are
      yellowish, and those on the outer, are brown on the anterior part,
      and white on the posterior. A small tuft of white hairs springs
      from the neck immediately behind the ears; this tuft is hidden
      when the ears are folded back. The tail is slender and short,
      (being not quite equal to the body in length) of a pale
      flesh-colour, and sparingly furnished with minute white hairs. The
      feet are very small and slender, and the naked parts are of a pale
      flesh-colour. The sole of the foot is covered with hairs; the toes
      beneath, and the tubercles (which are as in _Mus Musculus_),
      however, are naked. The hairs of the moustaches are of moderate
      length, and of a blackish colour, some of them, however, are
      grayish white.

                                                              In. Lines.
 Length    from nose to root of tail                            2     10
           of tail                                              1      7
           from nose to eye                                     0     4⅓
           from nose to ear                                     0     8¼
           of tarsus (claws included)                           0     6½
           of ear                                               0     4¼


  Habitat, Bahia Blanca, (_September_.)


This species slightly exceeds the harvest mouse (_Mus messorius_) in
size, its ears are considerably larger in proportion, and the tail is
shorter. Compared with the common mouse (_Mus Musculus_) it is smaller,
the tail is more slender, and shorter, and the feet are likewise more
slender and proportionately much smaller; the ears are more distinctly
clothed with hairs.

The principal points of distinction between this and the two preceding
species are pointed out in the account of _M. elegans_.

Upon comparing the skull of _M. gracilipes_ (Pl. 34, fig. 4. _a_.) with
that of _Mus Musculus_, the most striking differences consist in its
shorter and broader form, the upper surface being more arched, the
interparietal bone has a relatively smaller antero-posterior diameter,
the occipital region is more convex, and continued more gently and
gradually into the upper region of the skull. The zygomatic arch, which
is unusually slender, is more dilated (especially on the anterior part)
thus giving a squareness to the general form. The nasal bones are not so
much attenuated posteriorly. The length of the skull is 8⅞ lines, the
greatest width is 5⅛ lines, and the distance between the outer side of
the incisors and the front molar is 2¾ lines.

The dentition is figured in Plate 34, figs. 4. _b_ and 4. _c_.

“This specimen was given me by Mr. Bynoe, the surgeon of the Beagle, who
caught it amongst some long dry grass.”—D.


                            MUS FLAVESCENS.
                              PLATE XIII.

  Mus flavescens, _Waterh._, Proceedings of the Zoological Society of
  London, for February 1837, p. 19.

  _M. suprà colore cinnamomeo, lateribus capitis, corporisque, æquè ac
    pectore, auratis; gulâ abdomineque flavescenti-albis: pedibus
    sordidè albis: auribus mediocribus rotundatis, pilis flavis obsitis:
    caudâ, corpore, capiteque longiore, suprà fuscâ, subtùs sordidè
    albá: tarsis longis._

  DESCRIPTION.—Fur long and moderately soft; general colour of the upper
      parts bright brownish yellow; on the sides of the head and body
      bright yellow; towards the rump of a deeper hue, and inclining to
      orange; under parts pale yellow, or yellow-white; chest yellow.
      The fur both of the upper and under parts of the body deep
      plumbeous at the base. Feet flesh-colour, covered above with white
      hairs: tarsi long, naked beneath. Ears small, tolerably well
      clothed with hairs; those on the inner side yellow, but many of
      them blackish at the base; on the outer side, the hairs are
      blackish on the fore part and yellow on the hinder part. The hairs
      of the ordinary fur of the back are of a deep rich yellow colour
      at the tip, and the longer hairs are blackish. The tail is long,
      deep brown above and whitish beneath, the hairs of the moustaches
      are rather short and slender, and of a brownish colour. Thumb nail
      small and rounded.

                                                              In. Lines.
 Length    from nose to root of tail                            3      9
           of tail                                              4     1½
           from nose to ear                                     1      0
           of tarsus                                            1     0½
           of ear                                               0     4½


  Habitat, Maldonado, La Plata, (_June_.)


This species is slightly larger than the common mouse; the head is
rather larger in proportion; the ears are rather smaller and more
distinctly clothed with hair; the tail and tarsi are much longer in
proportion. Its bright yellow colouring and proportions distinguish it
from any of the species described in this work. Of this animal I do not
possess the skull, nor of the teeth do I possess more than the first and
second molars of the upper jaw, and the second and last of the lower
jaw. These are figured in Plate 34, figs. 5. _a_, and 5. _b_.


                           MUS MAGELLANICUS.
                               PLATE XIV.

  Mus Magellanicus, _Bennett_, Proceedings of the Zoological Society of
  London for December 1835, p. 191.

  _M. suprà fuscus, subtùs cinerescenti-albus, pallidè flavo lavatus;
    auribus mediocribus pilis fuscis obsitis; caudâ corpus caputque
    æquante; tarsis longis, pilis sordidè albis obsitis._

  DESCRIPTION.—Fur very long and moderately soft, general colour deep
      brown; the hairs of the ordinary fur are gray, tipped with
      yellowish brown; the longer hairs are black; the sides of the body
      are yellowish; the under parts are gray-white with a faint
      yellowish tint, each hair being gray tipped with yellowish white.
      The ears are rather small, well clothed with hairs; those on the
      inner side are blackish tipped with yellow, and on the outer side
      they are blackish on the fore part and dusky on the hinder part.
      The fore feet are of moderate size, the thumb nail is short and
      rounded; the tarsi are rather long; both fore and hinder feet are
      of a brownish colour, and covered above with dirty gray hairs. The
      tail rather exceeds the head and body in length; it is brown above
      and dirty white beneath. The hairs of the moustaches are numerous
      and long, of a brownish colour at the apex and black at the base.

                                                              In. Lines.
 Length    from nose to root of tail                            4      3
           of tail                                              4      2
           from nose to ear                                     1     0½
           of tarsus                                            1      1
           of ear                                               0      5


  Habitat, Port Famine, Strait of Magellan.


This mouse is larger than _Mus Musculus_; the tail is rather longer in
proportion; the tarsi much longer; the ears are not quite so large in
proportion to the head, (which greatly exceeds that of _Mus Musculus_ in
size,) and they are densely clothed with hair. The fur is longer. In
colour, the animal here described is rather darker than the common
mouse. I have one specimen however before me which _very nearly_ agrees
in this respect.

The dentition is figured in Plate 34, figs. 6, _a._ and 6, _b_.

From the attention which Mr. Darwin bestowed upon the Muridæ of the
southern parts of South America, I presume his collection affords
materials for a tolerably complete monograph of the species of that
portion of the globe. The species above described, however, does not
occur in Mr. Darwin s collection, but is here introduced in order to
make the work more complete, and that I might more clearly point out the
distinctions which exist between it and other species here described,
the account given by Mr. Bennett in the Proceedings being very short.


                             MUS ARENICOLA.
                              PLATE XIII.

  Mus arenicola, _Waterh._, Proceedings of the Zoological Society of
  London, for February 1837, p. 18.

  _M. suprà fuscus, subtùs cinerescenti-albus, pallidè flavo tinctus;
    auribus mediocribus rotundatis, pilis flavis fuscisque obsitis;
    caudâ quoad longitudinem corpus æquante; pedibus cinerescenti-albis:
    tarsis mediocribus._

  DESCRIPTION.—Fur long, moderately soft; general colour deep brown;
      sides of the body with a very obscure yellowish hue; under parts
      dirty gray with a faint yellow tint. All the fur deep gray at the
      base; the hairs of the upper part of the body obscurely annulated
      with yellowish brown near the apex, and dusky at the apex; the
      longer hairs are black. Feet brownish, covered above with
      brown-white hairs; tarsi short. Tail short, blackish above,
      brown-white beneath. Ears small, well clothed with hairs; those on
      the inner side are yellow at the apex and gray at the base; on the
      outer side they are of a brownish colour, and on the fore part
      blackish. The hairs of the moustaches are short and slender, and
      of a brownish colour. The head is large.

                                                              In. Lines.
 Length    from nose to root of tail                            4      3
           of tail                                              2      9
           from nose to ear                                     1      0
           of tarsus (claws included)                           0     10
           of ear                                               0     4½


  Habitat, Maldonado, La Plata, (_June_.)


This species is rather larger than the common mouse; its head is
proportionately larger, the ears are smaller, the tail considerably
shorter, and the fur longer, and in colouring it is a little darker. In
size and colour it resembles _M. Magellanicus_, but the shorter tail and
tarsi, and the smaller size of the ears will serve to distinguish it.

The skull of _Mus arenicola_, Plate 34. fig. 7, _a_, is rather larger
than that of _Mus Musculus_, the nasal portion is broader, the
interparietal bone is much smaller, especially in antero-posterior
extent; the zygomatic arches are more slender, and the incisive foramina
are broader. The horizontal ramus of the lower jaw (Pl. 34. fig. 7,
_d._) is rather less curved, the coronoid process is more elongated, and
the condyloid is narrower and also larger. The length of the skull is 11
lines and a half; the width is 6½ lines. The molars of the upper jaw are
figured in plate 34 fig. 7, _b._ and those of the under jaw, fig. 7,
_c_.

“This specimen was caught on the open grassy plain, by a trap baited
with a piece of bird; it is, however, very abundant in the sand hillocks
near the coast of the Plata.”—D.


                          13. MUS BRACHIOTIS.
                               PLATE XIV.

  Mus brachiotis, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 17.

  _M. suprà obscurè fuscus, subtùs obscurè griseo tinctus; pedibus
    griseo-fuscis; auribus parvulis; caudâ quoad longitudinem, corpus
    ferè æquante: vellere longo et molli._

  DESCRIPTION.—Fur soft, very long, and dense; ears very small; general
      colour brown: the hairs of the upper parts, and sides of the head
      and body are of a deep gray at the base, black at the apex, and
      narrowly annulated with deep yellow near the apex; on the throat
      and belly they are of a paler gray at the base, and grayish white
      at the apex. The ears are well clothed with brown hairs both
      within and without, and are for the most part hidden by the long
      fur of the head. The hairs covering the upper side of the feet are
      of a palish ashy-brown colour, and the fleshy portion appears to
      have been brown. The tail is well clothed with hairs, so that the
      scales are scarcely visible; on the upper side of the tail the
      hairs are brownish black, and on the under side, they are dirty
      white. The incisors are very slender; those of the upper jaw are
      of a very pale yellow colour, and those of the lower are white, or
      nearly so. The muzzle is slender, and pointed.

                                                              In. Lines.
 Length    from nose to root of tail                            4      9
           of tail                                              2      8
           from nose to base of ears                            1      2
           of tarsus (claws included)                           0     11
           of ear                                               0      3


  Habitat, Chonos Archipelago, (_December_.)


This mouse is considerably larger than _Mus Musculus_, and the great
length and density of its fur, causes it to appear much stouter in its
proportions; its colouring is darker, the tips of the hairs being much
more narrowly annulated with yellow than in that species. The very small
size of the ears will serve to distinguish the present animal from its
congeners—_Mus longipilis_, _M. Renggeri_, _M. arenicola_, &c.

The molar teeth of the upper jaw are figured in Plate 34. fig. 8, _a_;
and fig. 8, _b_, represents the middle and last molars of the lower jaw.

“Inhabited a very small island, covered with thick forest, in the
central part of the Chonos Archipelago.”—D.

A mouse obtained on the islets adjoining the east coast of Chiloe (where
Mr. Darwin says it was common) differs from the above in being a little
smaller, the tail is rather longer, and the ears are a trifle larger. In
the feet, claws, colouring and character of the fur it agrees, and
likewise in the pale colour and slenderness of the incisors. Its
dimensions are as follows:—

                                                              In. Lines.
 Length    from nose to root of tail                            4      0
           of tail                                              3      0
           of tarsus (claws included)                           0     10
           from nose to ear                                     0    10½
           of ear                                               0      4

I have not the means of satisfying myself whether this be a distinct
species or not; but I think it is not.

“The nature of the country where this specimen was procured is nearly
the same as in that part of the Chonos Archipelago, 150 miles to the
south, where the first was obtained.” D.


                           14. MUS RENGGERI.
                           PLATE XV.—Fig. 1.

Mus olivaceus, _Waterh._, Proceedings of the Zoological Society of
London, for February 1838, p. 16.

  _M. corpore suprà subolivaceo, subtùs cinerescente; auribus
    mediocribus, rotundatis, pills parvulis fuscescentibus obsitis;
    caudâ corpore breviore, pilosâ, suprà fuscâ subtùs albescente;
    pedibus pilis fuscescentibus tectis._

  DESCRIPTION.—Fur moderate; ears moderate; tail shorter than the body;
      general colour gray washed with yellow; under parts grayish white.
      On the upper parts and sides of the head and body the hairs are
      gray, broadly annulated with yellow near the apex, and dusky at
      the apex; the mixture producing a yellowish gray tint, approaching
      somewhat towards olive:—the hairs on the under parts of the body
      and throat are deep gray at the base, and white at the apex; the
      hairs of the feet are brownish-white. The tail is tolerably well
      clothed with hairs; those on the upper surface are brown, and
      those on the under are dirty white. The ears are well clothed,
      both externally and internally, with hairs of the same colour as
      those on the upper parts of the body. The hairs of the moustaches
      are for the most part whitish, and black at the base. The upper
      incisors are pale yellow, and the lower incisors are yellowish
      white.

                                                              In. Lines.
 Length    from nose to the root of tail                        5      1
           of tail                                              2      8
           from nose to base of ears                            1      2
           of tarsus (claws included)                           0     11
           of ear.                                              0      5


  Habitat, Valparaiso (_August and September_,) Coquimbo (_May_.)


Subsequent to the description of this species, under the name of _M.
olivaceus_ in the Zoological Society’s Proceedings, I have imagined that
perhaps that name might mislead as regards the colouring of the
animal;—it certainly has a slight olive hue, but it is not very evident.
I have therefore changed the name, and substituted that of the author of
the “Naturgeschichte der Säugethiere von Paraguay,” &c.

In the collection there are three specimens of the present species; in
one of these the hairs of the upper part and sides of the body are
annulated with yellowish white, instead of yellow; hence the general hue
of these parts is nearly gray.

_Mus Renggeri_ is larger than _Mus Musculus_, and much stouter in its
proportions; the fur is shorter, much less dense, and less soft than in
_Mus brachiotis_.

“It inhabits dry stony places, where only a few thickets grow.”—D.


                           15. MUS OBSCURUS.
                           PLATE XV.—Fig. 2.

  Mus obscurus, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 16.

  _M. suprà fusco-nigrescens, subtùs flavescens; pedibus obscurè fuscis;
    unguibus longiusculis; auribus mediocribus; caudâ corpore breviore,
    suprà nigrescente, subtùs sordidè albâ; vellere mediocri, molli._

  DESCRIPTION.—Head large; ears moderate; tail shorter than the body;
      fur rather long and glossy; the general hue of that of the upper
      parts and sides of the head and body is blackish brown, and that
      of the under parts is dirty yellowish white. The hairs on the
      upper parts are of a deep lead colour at the base, black at the
      apex, and narrowly annulated with dark yellow near the apex; those
      of the throat and belly are lead colour at the base and yellowish
      at the tip; the chin is white: around the eye, and on the lower
      part of the cheeks a deep yellow tint prevails. The ears are well
      clothed with hairs both externally and internally, and these are
      for the most part of a deep brown colour, as are also the hairs
      which cover the feet. The tail is well clothed with hairs, those
      on the upper surface are black, and those on the under are dirty
      white. Both upper and lower incisors are yellow, but the lower are
      paler than the upper.

                                                              In. Lines.
 Length    from nose to root of tail                            5      3
           of tail                                              2      7
           from nose to ears                                    1     2½
           of tarsus (claws included)                           0    11½
           of ear                                               0      4


  Habitat, Maldonado, La Plata, (_June_.)


The present species, like the foregoing, is much stouter than the common
mouse (_Mus Musculus_), its colour is much darker. In possessing a
glossy fur it differs from most of its congeners; its head is also
proportionately larger, and the incisors are much stronger.

The molars of the upper jaw are figured in plate 34, fig. 9, _a_,—and
fig. 9, _b_, represents those of the under jaw.

“Very abundant in gardens and hedges, far from houses; and was easily
caught in traps baited either with cheese or meat.”—D.


                         16. MUS XANTHORHINUS.
                          PLATE XVII.—Fig. 1.

  Mus xanthorhinus, _Waterh._, Proceedings of the Zoological Society of
  London, for January 1837, p. 17.

  _M. suprà fuscus flavo lavatus; subtùs albus; rhinario flavo; auribus
    parvulis, intùs pilis flavis obsitis; mystacibus longis, canis, ad
    basin nigrescentibus: caudâ corpore breviore, suprà fuscâ, ad latera
    flavescente, subtùs sordidè albâ: pedibus anticis, tarsisque flavis,
    digitis albis: vellere longo, molli._

  DESCRIPTION.—Fur moderately long and loose; ears rather small; tail
      shorter than the body; general colour gray washed with yellow, the
      yellow colour prevailing, especially on the sides of the body;
      muzzle, inner side of ears, and tarsus, of a rich yellow colour;
      toes, chin, throat, under parts of body, and rump, white; all the
      fur deep gray at the base; the hairs on the upper parts and sides
      of the body broadly annulated near the apex with rich yellow, and
      at the apex dusky; on the under parts of the body the hairs are
      broadly tipped with white. Tail rather sparingly furnished with
      hair, that on the upper surface brown, on the sides yellow, and on
      the under surface whitish. The hairs of the moustaches are
      white—some of them dusky at the base. The incisor teeth are rather
      slender, and of a pale yellow colour.

                                                              In. Lines.
 Length    from nose to root of tail                            3      6
           of tail                                              1     7½
           from nose to ear                                     0     10
           of tarsus (claws included)                           0      9
           of ear                                               0     3¾


  Habitat, Hardy Peninsula, Tierra del Fuego, (_February_.)


The white, which is usually confined to the under parts of the body, in
this species extends slightly on the sides of the body, and the lower
portion of the cheeks.

“This species was caught on the mountains, thickly covered with peat, of
Hardy Peninsula, which forms the extreme southern point of Tierra del
Fuego.”—D.


                           17. MUS CANESCENS.

  Mus canescens, _Waterh._, Proceedings of the Zoological Society of
  London for February, 1837, p. 17.

  _M. suprà canescens, subtùs albus; oculis flavido cinctis; auribus
    parvulis, pilis pallidè flavis et plumbeis obsitis; mystacibus
    mediocribus, canis, ad basin nigricantibus; caudâ vix corpore
    breviore, suprà fusco-nigrâ, subtùs sordidè albâ; pedibus anticis
    tarsisque flavescentibus._

  DESCRIPTION.—Fur moderately long and loose; ears small; tail nearly
      equal to the body in length: general colour gray, with a wash of
      very pale yellow; chin, throat, and under parts of the body,
      white. Tail tolerably well clothed with hairs, those on the upper
      surface brown, and those on the under, whitish; on the sides are
      some yellowish hairs. Ears with yellow hairs on the inner side;
      tarsi pale yellow, toes white; muzzle and around the eye
      yellowish.

                                                              In. Lines.
 Length    from nose to root of tail                            3  6[21]
           of tail                                              2      1
           from nose to ear                                     1      1
           of tarsus (claws included)                           0     9½
           of ear                                               0      4


  Habitat, Santa Cruz and Port Desire, (_December_.)


“Very common in long dry grass in the valleys of Port Desire.”—D.

The skull is figured in Plate 33, fig. 5, _c_. Fig. 5, _a._ represents
the molars of the upper jaw; fig. 5, _b._ those of the under jaw, and
fig. 5, _d._ represents the posterior molar of the under jaw when more
worn.

It was with some hesitation that I described this as a distinct species
in the Society’s Proceedings. I have now re-examined the specimens, and
still am unable to satisfy myself whether they are varieties of _Mus
xanthorhinus_ or not. Both of _Mus canescens_ and of _Mus xanthorhinus_,
I have before me what I imagine to be an adult and a young specimen. The
adult and the young of _M. xanthorhinus_ agree in being of a _yellowish
brown_ colour, and in having the muzzle and tarsi deep yellow; both
specimens of _Mus canescens_ are of a _gray_ colour, with an indistinct
yellow wash, the muzzle and tarsi being tinted with yellow, as in _M.
xanthorhinus_. Besides this difference in tint, which, perhaps, is
unimportant, _M. canescens_ differs from _M. xanthorhinus_ in having the
head larger, the tail rather longer, and the fur less soft. The
specimens of this animal are both from Patagonia; one of the specimens
of _Mus xanthorhinus_ was brought by Mr. Darwin from Terra del Fuego;
and as the other formed part of Captain King’s collection, it in all
probability came from the same locality. As I only possess one skull, I
cannot speak with certainty as regards the size of the head; the
difference, however, in the stuffed specimens is considerable, and it is
strange that each of the pairs should agree so perfectly, supposing the
difference to be the work of the stuffer’s hands.


                          18. MUS LONGIPILIS.
                               PLATE XVI.

  Mus longipilis, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 16.

  _M. suprà obscurè griseus, flavo lavatus; subtùs griseus; pedibus
    fuscis, unguibus longiusculis; auribus mediocribus; caudâ corpore
    breviore, suprà nigrescente, subtùs fuscescente; rhinario
    sub-producto: vellere longissimo, molli._

  DESCRIPTION.—Fur very soft and silky, and extremely long—the ordinary
      fur of the back measuring nearly three quarters of an inch, and
      the longer hairs one inch in length; ears moderate; tail nearly as
      long as the body; muzzle much pointed; general colour gray, washed
      with yellow, the under parts pale gray, or grayish white; feet
      brown; ears and tail well clothed; the hairs on the inner side of
      the ears are chiefly of a yellow colour, those on the upper
      surface of the tail are brown-black, those on the under part are
      dirty white; the hairs of the back are deep gray at the base,
      broadly annulated with yellow near the apex, and dusky at the
      apex; the longer hairs are grayish black; the hairs of the
      moustaches are dusky at the base, and whitish beyond that part;
      the claws are long, and but slightly curved; the incisors are
      slender; those on the upper jaw are yellow, and those of the under
      yellow-white.

                                                             In.  Lines.
 Length    from nose to root of tail                           5       4
           of tail                                             3       4
           from nose to ear                                    1       2
           of tarsus (claws included)                          1      0½
           of ear                                              0      6½


  Habitat, Coquimbo, Chile, (_May_.)


This mouse is remarkable for the great length and softness of its fur,
even among the species here described, most of which have very loose,
long and soft fur.

The molars of the upper jaw are figured in Plate 33, fig. 6, _b._—molars
of the lower jaw, fig. 6, _a_.

“Inhabits dry stony places, which character of country is general in
this part of Chile.”—D.


                            19. MUS NASUTUS.
                          PLATE XVII.—Fig. 2.

  Mus nasutus, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 16.

  _M. suprà obscurè flavescenti-fuscus, ad latera fulvescens; subtùs
    obscurè fulvo tinctus: pedibus pilis obscurè fuscis tectis; unguibus
    longis; auribus mediocribus; caudâ corpore breviore, suprà fuscá,
    subtùs sordidè albâ: rhinario producto._

  DESCRIPTION.—Muzzle very long and pointed, ears small, tail shorter
      than the body, claws long and but slightly arched; inner,
      rudimentary toe of the fore foot furnished with a pointed claw;
      fur moderate, and slightly glossy: general colour yellowish brown,
      of the sides of the body yellow, of the under parts pale yellow;
      the chin, throat and chest whitish: feet brown; ears well clothed
      with hairs, those on the inner side are most of them yellow, but
      some are black. All the fur is of a deep lead colour at the base;
      the hairs on the upper parts and sides of the head and body are
      broadly annulated with deep golden yellow near the apex, and
      blackish at the apex; on the upper parts long brownish black hairs
      are thickly interspersed with the ordinary fur, but on the side of
      the body they are less numerous, hence on this part the yellow
      tint prevails; on the under parts of the body the hairs are
      broadly tipped with pale yellow, and in parts with white: the tail
      is but sparingly clothed with hairs, those on the upper surface
      are of a dark brown colour, and those on the under are pale brown.
      The incisors are very slender and of a very pale yellow colour.

                                                              In. Lines.
 Length    from nose to root of tail                            5      2
           of tail                                              2      8
           from nose to ear                                     1      3
           of tarsus (claws included)                           1     0½
           of ear                                               0      5


  Habitat, Maldonado, La Plata, (_June_.)


The specific name _nasutus_ has been applied to this mouse on account of
its elongated and slender muzzle[22], the tip of which extends nearly 4
lines beyond the upper pair of incisors: the rudimentary toe of the fore
foot, instead of having the usual rounded nail, has a short pointed
claw. Its fur is not so soft, nor yet so long as in many of the
preceding species, and there is a greater admixture of yellow in its
colouring. The claws appear to be adapted to burrowing.

The skull (which is not quite perfect) is figured in Plate 33, fig. 7,
_a_, its length is 1 in. 3 lines. Fig. 7, _b_, represents the molars of
the upper jaw, and fig. 7, _c_, those of the under jaw. The lower jaw,
which is of a very slender and elongated form, is figured in Plate 34,
fig. 10, _a_.

“Was caught in a small thicket on an open grassy plain, by a trap baited
with a piece of bird. This mouse when alive possesses a marked character
in the extreme acumination of its nose.”—D.


                            20. MUS TUMIDUS.
                              PLATE XVIII.

  Mus tumidus, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 15.

  _M. brunneus, nigro lavatus; rostro ad apicem, labiis, mento, gulâ,
    pectore, abdomineque albis; naso suprà nigrescente; auribus
    mediocribus rotundatis; corpore crasso; caudâ capite corporeque
    breviore, pilis nigricantibus, subtùs albescentibus prope basin,
    vestitâ; artubus pedibusque grisescentibus; vellere longo, molli;
    unguibus longis._

  DESCRIPTION.—Body stout; head large; tail nearly as long as the head
      and body; inner toe of the fore foot with a distinct, pointed
      claw; claws rather large, those of the fore feet but slightly
      arched. Fur rather long, and moderately soft; general tint of the
      upper parts of the body, brown, of the sides of the head and body,
      grayish, but with a yellow wash; the lower part of the sides of
      the body and of the cheeks, the tip of the muzzle, and the whole
      of the under parts, white; feet dirty white; ears densely clothed
      with short hairs, those on the inner side chiefly of an ashy-brown
      colour, and those on the outer side dusky; the hairs of the back
      are of a deep lead colour at the base, black at the tip, and
      annulated with yellow near the tip; the longer hairs, which are
      thickly interspersed, are totally black; on the under parts of the
      body the hairs are gray at the base, and broadly tipped with
      white; the upper surface of the muzzle is blackish; the moustaches
      are black; the incisors are yellow.

                                                              In. Lines.
 Length    from nose to the root of tail                        6      9
           of tail                                              5      4
           from nose to ears                                    1      8
           of tarsus (claws included)                           1      6
           of ear                                               0      7


  Habitat, Maldonado, La Plata (_June_.)


This species is about the size of _Mus Rattus_, but is stouter in its
proportions; as in _Mus nasutus_, the thumb is furnished with a pointed
claw. The molars of the lower jaw are figured in Plate 34, fig. 11, _a_.

“This rat was caught in so wet a place amongst the flags bordering a
lake, that it must certainly be partly aquatic in its habits.”—D.


                         21. MUS BRAZILIENSIS.
                               PLATE XIX.

  Rat du Brézil, _Geoff._

  _M. suprà fuscus fulvo lavatus; lateribus capitis corporisque æquè ac
    abdomine auratis; gulâ pectoreque albis; pedibus pilis sordidè
    flavis tectis; auribus parvulis; caudâ caput corpusque ferè æquante;
    vellere longo, molli._

  DESCRIPTION.—Head somewhat arched, and rather short; ears small; tail
      about equal in length to the head and body, measured in a straight
      line; tarsi large. Fur long, and rather soft; general colour deep
      golden yellow: on the upper surface of the head and the back, long
      glossy black hairs are thickly interspersed, and produce, with the
      admixture of the deep golden colour of the ordinary fur, a dark
      brown tint; chin, throat, chest, and rump, white; the hairs
      covering the upper surface of the feet are of a dirty yellowish
      white colour, and on the toes nearly white: ears densely clothed
      with longish hairs, those on the inner side chiefly of a deep
      golden colour, and those on the outer side brownish; the ears are
      partially hidden by the long fur of the head; tail sparingly
      clothed with hairs, above brown, and beneath brownish-white: the
      fur of the back is of a deep gray colour at the base, annulated
      with deep golden yellow near the apex, and blackish at the apex;
      the longer hairs are black; the hairs of the belly are pale gray
      at the base, and broadly tipped with golden yellow colour; the
      white hairs on the throat, chest, and rump are of an uniform
      colour—not tinted with gray at the root;—the hairs of the
      moustaches are black: the incisors of the upper jaw are of a deep
      orange colour, and those of the lower jaw are yellow: the thumb
      nail is truncated.

                                                              In. Lines.
 Length    from nose to root of tail                            8      6
           of tail                                              7      9
           from nose to ear                                     1      8
           of tarsus                                            2      0
           of ear                                               0     6½


  Habitat, Bahia Blanca, (_September_.)


This species is nearly equal in size to the common rat (_Mus
decumanus_). Of its skull[23] I possess but the anterior portion (see
Pl. 33. fig. 3, _a._ and 3, _b._): it appears to have been about the
same size as that of _M. decumanus_, its proportions, however, are
different: the nasal portion is broader and shorter, the ant-orbital
outlet is rather smaller; the plate, forming the anterior root of the
zygomatic arch, and which protects this outlet, has its anterior edge
distinctly emarginated, and not nearly straight as in _M.
decumanus_,—the zygomatic arch is stouter, the space between the orbits
is narrower, the palate is more contracted, the incisors are much
broader, less deep from front to back, and have the anterior surface
more convex; the molar teeth are larger; the lower jaw (see Plate 34.
fig. 12, _a._) when compared with that of _Mus decumanus_ also offers
many points of dissimilarity; the principal differences consist in its
greater strength, the comparatively large size and breadth of the
articular surface of the condyles, the upright position of the coronoid
process—a perpendicular line dropt from the apex of which would touch
the posterior part of the last molar—and the great extent of the
_symphysis menti_. In the form of the incisors, the more contracted
palate, the great extent of the _symphysis menti_, and in fact in most
of the points of dissimilarity, between the skull of the present animal
and that of _Mus decumanus_, here pointed out, it will be perceived,
there is an approach made to the _Arvicolidæ_.

The dimensions of the skull (so far as an imperfect specimen will allow
of their being taken) are as follows:—

                                                              In. Lines.
 Distance between front of incisors, (upper jaw) and the
   first molar tooth                                            0      8
 Longitudinal extent of the three molars on either side,
   taken together                                               0     4¼
 Length    of nasal bones                                       0     7¼
 ——        of incisive _foramina_                               0     4¼
 Width     between orbits                                       0     2½
 Length    of _ramus_ of lower jaw                              1     1¼

Fig. 3, _c_, Plate 33, represents the molar teeth of the upper jaw. Fig.
3, _d_, those of the upper jaw.

“This rat was caught at Bahia Blanca where the plains of Patagonia begin
to blend into the more fertile region of the Pampas. It lived in holes
amongst the tussocks of rushes, on the borders of a small, still, brook;
in its manner of diving and aquatic habits it closely resembled the
English water-rat, (_Arvicola amphibia_.)”—D.

When at Paris I examined what I believe to be the original _Mus
Braziliensis_, since the specimen was labelled “_Rat de Brazil St.
Hilaire, 1818_.” It agrees perfectly with the present animal excepting
in being rather smaller, the length from the nose to the tail being 7
inches and 4 lines—the length of the tail is 7 inches 9 lines, and that
of the tarsus is 1 inch 11 lines; this difference in the length of the
body may arise from difference of age, or even of sex. In the Paris
Museum I saw what appeared to me to be a variety of the same species in
which the under parts of the body are white.

I have been minute in my description of the _Mus Braziliensis_, since it
is confounded by Desmarest, Fischer and Lesson with the _Rat troisieme_
or _Rat Angouya_ of Azara, which I believe to be a very different
animal. The description given by the authors just mentioned are taken
from Azara, who gives the following characters to distinguish the _Rat
Angouya_: “Du museau à la queue, et sur les côtés du corps tout est
brun-cannelle, parceque les poils ont une petite pointe cannelle; puis,
ils sont obscurs et enfin blanc vers las peau. Toute la partie
inférieure de l’animal est blanchâtre, plus claire sous la tête, et plus
foncée entre les jambes de devant; le pelage est doux, très-serr, et le
poil, qui est à la racine de l’oreille, cache le conduit de celle-ci.”

                                                              In. Lines.
 Length    from nose to root of tail (English measure)          6      0
           of tail                                              6     6½
           of ears                                              0     9¾
           of tarsus (the claws included)                       1     3¼

It appears from this description that the _Mus Angouya_ is a smaller
animal, and differs both in colouring and proportions from the _Mus
Braziliensis_. Brandt has figured and described a rat under the name of
_Mus Angouya_, which in many respects agrees better with Azara’s
description; there are, however, discrepancies in the dimensions.


                           22. MUS MICROPUS.
                               PLATE XX.

  Mus micropus, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 17.

  _M. suprà fuscus; subtùs cinerescenti-albus, pallidè flavo tinctus;
    pedibus pilis sordidè albis tectis, antipedibus parvulis; auribus
    parvulis; caudâ, quoad longitudinem, corpus ferè æquante, suprâ
    fuscâ, subtùs sordidè albâ._

  DESCRIPTION.—Form stout, ears rather small, tail nearly equal to the
      body in length, fur very long and moderately soft, general colour
      of the upper parts of head and body, brown; of the sides of the
      body grayish, faintly washed with yellow, of the under parts
      grayish white, faintly tinted with yellow; hair covering the upper
      surface of the feet dirty white; on the tarsus there is a very
      slight yellow tint; ears well clothed with hairs, those on the
      inner side chiefly of a yellow colour; tail above, dusky brown;
      beneath dirty white: hairs of moustaches black at the base and
      grayish at the apex; incisors pale yellow: hairs of the back deep
      gray at the base, annulated with brownish yellow near the apex,
      and dusky at the apex; longer hairs dusky black; hairs of the
      belly deep gray at the base and broadly tipped with yellowish
      white.

                                                              In. Lines.
 Length    from nose to root of tail                            6      0
           of tail                                              3      8
           from nose to ear                                     1      4
           of tarsus (claws included)                           1     0¾
           of ear                                               0      6


  Habitat, Santa Cruz, Patagonia, (_April_.)


The molars of the upper jaw are figured in Plate 34, fig. 13, _a_, and
those of the lower jaw, fig. 13, _b_.

“Caught in the interior plains of Patagonia in lat. 50°, near the banks
of the Santa Cruz.”—D.


                         23. MUS GRISEO-FLAVUS.
                               PLATE XXI.

  Mus griseo-flavus, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 28.

  _M. suprà griseus flavo-lavatus, ad latera flavus, subtùs albus;
    pedibus albis; auribus magnis et ferè nudis; caudâ caput corpusque
    ferè æquante, suprà fusco-nigricante, subtùs albâ; vellere longo,
    molli._

  DESCRIPTION.—Ears large; tail rather shorter than the head and body
      taken together; tarsi slender, and moderately long; fur long and
      very soft; general tint of the upper parts of head and body
      grayish, washed with brownish yellow; on the sides of the body a
      palish yellow tint prevails; feet, chin, throat, and under parts
      of body pure white; tail rather sparingly clothed with hairs,
      those on the apical portion rather long, and forming a slight
      pencil at the tip; on the upper side and at the tip of the tail
      the hairs are brown, on the under side they are dirty white; the
      ears are very sparingly clothed with minute brownish yellow hairs
      internally; externally, on the fore part, the hairs are rather
      longer and of a brown colour; the upper incisors are orange, and
      the lower incisors are yellow; the hairs of the moustaches are
      long, and of a black colour; the hairs of the back are deep gray
      at the base, brownish at the tip, and annulated with pale brownish
      yellow near the tip; the longer hairs are brown; the hairs of the
      belly are white externally, and gray at the base; on the throat
      the hairs are white to the root.

                                                              In. Lines.
 Length    from nose to root of tail                            6      8
           of tail                                              5      6
           from nose to ear                                     1     4½
           of tarsus (claws included)                           1     2½
           of ear                                               0      8


  Habitat, Northern Patagonia (_August_.)


The molars of the upper jaw are figured in Plate 34, fig. 15, _a_, and
those of the lower jaw, fig. 15, _b_.

“Inhabits the dry gravelly plain, bordering the Rio Negro.”—D.


                          24. MUS XANTHOPYGUS.
                              PLATE XXII.

  Mus xanthopygus, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 28.

  _M. suprà pallidè brunneus flavo-lavatus, ad latera flavescens, subtùs
    albus; capite griscescente; natibus flavis; pedibus albis; auribus
    majusculis pilis, albis et flavis intermixtis obsitis; caudâ quoad
    longitudinem, corpus ferè æquante, suprà nigricante, subtùs albâ;
    vellere longo et molli; mystacibus perlongis albescentibus, ad basin
    nigris._

  DESCRIPTION.—Ears rather large, tail rather longer than the body,
      tarsi moderately long and somewhat slender: fur long and very
      soft: prevailing tint pale yellow; on the back there is a brownish
      hue owing to the long hairs, which are thickly interspersed with
      ordinary fur, being of that colour: in the region of the tail the
      hairs are of a rich yellow colour; the tip of the muzzle is white,
      the feet, chin, throat and the whole under parts of the body are
      white; on the chest and belly a faint yellowish hue is observable:
      the tail is well clothed with tolerably long hairs, those on the
      apical portion are the longer, on the upper side of the tail they
      are of a brown colour, and on the under side they are pure white:
      the ears are well clothed with tolerably long hairs, those on the
      inner side are of a pale yellowish colour, externally on the fore
      part they are brown, and on the hinder part they are yellowish
      white: the hairs of the moustaches are numerous and very long;
      some of them are white, but the greater portion are brownish black
      at the base and whitish at the apex: the upper incisors are
      yellow, and the lower are yellow-white: the hairs of the ordinary
      fur on the back are gray at the base, brownish at the tip, and
      very pale yellow near the tip: the hairs on the belly are gray at
      the base and white externally.

                                                              In. Lines.
 Length    from nose to root of tail                            5      3
           of tail                                              3     10
           from nose to ear                                     1      3
           of tarsus (claws included)                           1      1
           of ear                                               0      7

There are three specimens of the present species in Mr. Darwin’s
collection; two of them were caught when shedding their fur, and having
lost the longer black hairs, have the upper parts of the body of a paler
colour; their general tint is very pale, and may be described as gray,
with a wash of pale yellow.

This species is closely allied to the last, but differs in being rather
smaller, in having smaller ears which are well clothed with hair, and
not sparingly furnished as in _Mus griseo-flavus_, and in having a
shorter tail which, like the ears, is more densely clothed with hairs;
in the structure of the molar teeth there also differences which will be
better understood by comparing the drawings. Fig. 16, _a_, Plate 34,
represents the molars of the upper jaw, and 16, _b_, those of the lower
jaw.

“Extremely abundant in the coarse grass and thickets in the ravines at
Port Desire and Santa Cruz: was caught in a trap baited with cheese.”—D.


                           25. MUS DARWINII.
                              PLATE XXIII.

  Mus Darwinii, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 28.

  _M. suprà pilis pallidè cinnamomeis et nigrescentibus intermixtis;
    ante oculos cinerascentibus; genis, lateribus corporis, et caudâ
    prope basin, pallidè cinnamomeis; partibus inferioribus pedibusque
    albis; auribus permagnis; caudâ caput corpusque ferè æquante, suprà
    fusco-nigricante, subtùs albâ._

  DESCRIPTION.—Form robust; ears immensely large; tail nearly equal in
      length to the head and body taken together; fore feet very small;
      tarsi moderate; fur very long and soft; general tint of the upper
      parts pale cinnamon yellow; on the rump a richer yellow hue
      prevails, and on the back there is a brownish tint, owing to the
      interspersed long hairs being of that colour; the upper surface of
      the head is grayish; the cheeks, like the sides of the body, are
      of a delicate yellow colour, faintly clouded with brown; the sides
      of the muzzle, lower part of the cheeks and sides of the body, and
      the whole under parts, are pure white; the feet and tail are also
      white, if we except the upper surface of the latter, which is dark
      brown; the yellow tint of the sides of the body is extended
      downwards on the outer side of the fore legs and on the back of
      the hinder legs; the ears are but sparingly furnished with hair,
      excepting on the fore part, externally, where they are of a
      brownish colour; the minute hairs which cover the remaining parts
      of the ear are very pale; the tail is well clothed with hairs; the
      hairs of the moustaches are numerous and very long; they are for
      the most part blackish at the base, and gray at the apex; the
      incisors are rather slender, the upper pair are an orange colour,
      and the lower, yellow; the hairs of the ordinary fur of the back
      are gray at the base, broadly annulated with pale cinnamon yellow
      near the apex, and brownish at the apex; the hairs of the belly
      are deep gray at the base, and white externally, those on the
      throat are pale gray at the base.

                                                              In. Lines.
 Length    from nose to root of tail                            6      0
           of tail                                              4      9
           from nose to ear                                     1     4½
           of tarsus (claws included)                           1     1½
           of ear                                               0    11¾
 Width     of ear                                               1 0½[24]


  Habitat, Coquimbo, Chile, (_May_.)


This species is evidently allied to the two preceding; and perhaps the
“Rat quatrieme, ou Rat oreillard” of Azara, (_Mus auritas_, Desm.) will
form one of this little group. The molar teeth of the upper jaw are
figured in Plate 34, fig. 17, _a_—those of the lower jaw, fig. 17, _b_.

“Inhabits dry stony places.”—D.


                         26. MUS GALAPAGOENSIS.
                              PLATE XXIV.

  _M. suprà fuscus, flavo-lavatus, ad latera flavescens, subtùs albus:
    pedibus pilis sordidè albis tectis: auribus mediocribus; caudâ,
    quoad longitudinem, caput corpusque ferè æquante: vellere longo._

  DESCRIPTION.—Ears moderate, slightly pointed; tarsi moderate; tail
      slender, nearly as long as the head and body; fur long, and not
      very soft; upper parts of the body of a brownish hue, a tint
      produced by the admixture of black and palish yellow hairs; on the
      sides of the body the longer black hairs are less abundant, and
      the prevailing colour is yellow; under parts of the body white,
      with a very faint yellow tint; feet furnished above with dirty
      white hairs; ears rather sparingly clothed with hairs, those on
      the inner side of a yellow colour, and those on the outer side
      dusky; tail above brown, and beneath whitish; the hairs of the
      moustaches black; the incisors deep yellow; the hairs on the back
      are deep gray at the base, broadly annulated with palish yellow
      near the apex, and blackish at the apex; the longer hairs black;
      on the belly the hairs are gray at the base, and broadly tipped
      with yellowish white.

                                                              In. Lines.
 Length    from nose to root of tail                            6      0
           of tail                                              4      9
           from nose to ear                                     1     3¾
           of tarsus (claws included)                           1      2
           of ear                                               0      7


  Habitat, Chatham Island, Galapagos Archipelago, Pacific Ocean,
  (_October_.)


This species is less than _Mus Rattus_. The upper parts of the body have
a slightly variegated appearance.

The skull of _Mus Galapagoensis_ (Plate 33, fig. 8, _a_,) is rather
smaller than that of _M. Rattus_, the nasal portion is proportionately
longer, the cranial shorter, and the interparietal bone is smaller,
especially in antero-posterior extent; its length is 15 lines, and its
breadth is 8⅛ lines. The lower jaw is figured in Plate 34, fig. 14, _a_.
Fig. 8, _b_, of Plate 33, represents the molars of the upper jaw, and
fig. 8, _c_, those of the lower jaw.

“This mouse or rat is abundant in Chatham Island, one of the Galapagos
Archipelago. I could not find it on any other island of the group. It
frequents the bushes, which sparingly cover the rugged streams of
basaltic lava, near the coast, where there is no fresh water, and where
the land is extremely sterile.”—D.


                           27. MUS FUSCIPES.
                               PLATE XXV.

  _M. suprà fusco-nigrescens, subtùs griseus; pedibus fuscis; auribus
    mediocribus, caudâ, quoad longitudinem, caput corpusque ferè
    æquante: vellere longissimo, molli._

  DESCRIPTION.—Form stout; ears moderate; tail equal to the body in
      length; tarsi moderate; fur very long. General tint of the upper
      part and sides of the head and body blackish brown with an
      admixture of gray; of the under parts grayish white; feet brown,
      the hairs grayish at the tip: tail black and but sparingly clothed
      with short bristly hairs: ears rather sparingly clothed with
      hairs, which are for the most part of a brownish gray colour. The
      ordinary fur of the back is about ¾ of an inch in length and very
      soft—of a deep gray colour, broadly annulated with brownish yellow
      near the tip and blackish at the tip: the longer hairs which are
      black, measure upwards of 1¼ inches in length. The upper incisors
      are of an orange colour and the lower are black.

                                                              In. Lines.
 Length    from nose to root of tail                            6      6
           of tail                                              4      3
           from nose to ear                                     1      6
           of ear                                               0     6½
           of tarsus (claws included)                           1      1


  Habitat, Australia, King George’s Sound, (_March_.)


Mammalia not belonging to the order _Marsupiata_ are rare in the
Continent of Australia. Besides the Dog, we are acquainted with none
excepting a few species of Rodents, and these all belong to the family
_Muridæ_.

The present animal adds one to the limited number already known: in the
Museum of the Zoological Society there is another species, the
characters of which I will point out in the next description.

_Mus fuscipes_ is remarkable for the great length and softness of its
fur, and the brown colour of its feet: it is rather less than _Mus
Rattus_, and of a stouter form. Not having had an opportunity of
examining the molar teeth and the cranium of this animal, I cannot be
positive that it is a species of the genus _Mus_; in external characters
and the form of the incisor teeth, however, it agrees perfectly with the
animals of that genus.

“This animal was caught in a trap baited with cheese, amongst the bushes
at King George’s Sound.”—D.


                            28. MUS GOULDII.

  _M. vellere longo, molli, ochraceo, pilis nigricantibus adsperso, his
    ad latera rarioribus: corpore subtùs, pedibusque albis: auribus
    majusculis: caudâ, capite corporeque paulo breviore._

  DESCRIPTION.—Ears rather large and slightly pointed, tarsi slender and
      tolerably long; tail about equal in length to the body and half
      the head; fur long and soft; general colour pale ochreous yellow;
      on the back there are numerous long black hairs interspersed with
      the ordinary fur, which gives a darker hue and somewhat variegated
      appearance to that part; feet, chin, throat, and the whole under
      parts of the body white; ears brown, sparingly clothed with minute
      yellow hairs, both externally (excepting on the forepart, where
      they are brownish) and internally; tail brownish above, and
      yellowish white beneath; the hairs of the moustaches long, and of
      a brown colour; upper incisors deep orange, lower incisors yellow;
      claws white. The hair of the back is of a deep lead colour at the
      base, pale ochre near the apex, and dusky at the apex; the longer
      hairs are black; the hairs of the belly are deep gray at the base
      and broadly tipped with white.

                                                              In. Lines.
 Length    from nose to root of tail                            4      8
           of tail                                              3      6
           from nose to ear                                     1     0½
           of tarsus (claws included)                           1     0½
           of ear                                               0      7

  VAR. β.—General colour of the fur pale ochreous yellow, the feet,
      under side of the tail and the whole of the under parts, as well
      as the lower portion of the sides of the body, white; hairs of the
      back palish gray at the base, those of the belly indistinctly
      tinted with very pale gray at the roots; ears and moustaches pale
      brown.


  Habitat, New South Wales.


This species is about half-way between _Mus Rattus_ and _Mus musculus_
in size, and is remarkable for its delicate colouring. The molar teeth
are figured in Plate 34; fig. 18. _a_, represents the molars of the
upper jaw, and fig. 18. _b_, those of the lower.




                         GENUS—REITHRODON.[25]


  _Dentes primores ²⁄₂; inferioribus acutis, gracilibus, et anticè
    lævibus; superioribus gracilibus, anticè longitudinalitèr sulcatis._

  _Molares utrinque ³⁄₃ radicati; primo maximo, ultimo minimo: primo
    superiore plicas vitreas duas externè et internè alternatìm
    exhibente; secundo, et tertio, plicas duas externè, internè unam:
    primo inferiore plicas vitreas tres externè, duas internè; secundo,
    plicas duas externè, unam internè; tertio unam externè et internè,
    exhibentibus._

  _Artus inæquales: antipedes 4–dactyli, cum pollice exiguo: pedes
    postici 5–dactyli, digitis externis et internis brevissimis._

  _Ungues parvuli et debiles. Tarsi subtùs pilosi._

  _Cauda mediocris, pilis brevibus adpressis instructa._

  _Caput magnum, fronte convexo: oculis magnis: auribus mediocribus._

The present genus according to my views belongs to the family _Muridæ_.
The modifications of structure which have led me to separate it from the
genus _Mus_ are as follows:

  _External characters._—The most conspicuous points of distinction
    between the external characters of _Reithrodon_ and _Mus_ (if we
    regard _M. rattus_, _M. decumanus_ or _M. musculus_ as typical
    examples of that genus,) consist in the arched form of the head, the
    large size of the eyes, the stout form of the body, and the upper
    incisors being grooved. The ears, tail and feet are more densely
    clothed with hairs, and the tarsus is covered with hair beneath,—at
    least the hinder portion.

  _Cranium._—The skulls of the species of the present genus differ from
    those of the species of _Mus_ in being proportionately shorter and
    broader, and more arched; the facial portion of the skull is larger,
    compared with the cranial, the space between the orbits is narrower,
    and the orbits are larger; the palate is narrower and the incisive
    foramina are more elongated and larger. The pterygoids approximate
    anteriorly, so that the posterior _nares_ are greatly contracted. As
    in the genus _Mus_ the anterior root of the zygomatic arch is
    directed upwards from the plane of the palate, and forwards in the
    form of a thin plate, protecting an opening behind, which leads into
    the nasal cavity, and also forming the outer boundary both of the
    ant-orbital foramen, and a second opening whose outlet is directed
    upwards. This thin plate, however, is narrower than is usually found
    in the genus _Mus_. The most striking differences observable in the
    lower jaw consist in the smaller size of the coronoid process, and
    its being curved outwards; the condyloid process is narrower, and
    the angle of the jaw, or descending ramus, approaches more nearly to
    a quadrate form—the posterior edge of the jaw is more deeply
    emarginated.

  _Dentition._—The incisors are narrow and compressed as in the genus
    _Mus_, but they are less deep from front to back; those of the upper
    jaw (Plate 33. fig 2. _b._) have each a distinct longitudinal
    groove, which is situated nearer to the outer than to the inner edge
    of the tooth. Close to the inner edge of each of these teeth an
    indistinct second longitudinal groove may be seen by means of a
    lens. The lower incisors are nearly equal in width to the upper.

  The crowns of the molar teeth in the young _Reithrodon_ are higher
    than in _Mus_, and they are rootless; in the adult animal, however,
    they possess distinct roots. The folds of enamel form sigmoid
    flexures, are closely approximated to each other, and those of the
    opposite sides of the tooth meet.


                      1. REITHRODON CUNICULOÏDES.
                              PLATE XXVI.

  Reithrodon cuniculoïdes, _Waterh._, Proceedings of the Zoological
  Society of London for February 1837, p. 30.

  _R. suprà griseus, flavo-lavatus, pilis nigris intermixtis; abdomine
    guláque pallidè flavis; natibus albis; pedibus albis; auribus
    mediocribus, intùs pilis flavis, extùs pilis pallidè flavis,
    obsitis; pone aures, notâ magnâ albescenti-flavâ; caudâ corpore
    breviore, suprà pallidè fuscâ, subtùs albâ._

  DESCRIPTION.—Head rather large and arched; ears moderate; tail nearly
      as long as the body; tarsi rather long; fur long and very soft.
      General tint of the upper parts of the body grayish brown, with a
      considerable admixture of yellow; of the sides of the body grayish
      tinted with yellow; the lower portion of the cheeks, and the lower
      half of the sides of the body are of a delicate yellow colour; the
      under parts of the head and body are yellowish white; the fore
      part of the thighs is whitish; the rump, feet, and tail are white,
      excepting the upper surface of the latter, which is brown; behind
      each ear there is a patch of yellowish white hairs. The ears are
      tolerably well clothed with hairs; those on the inner side are for
      the most part of a yellow colour, but towards the posterior margin
      they are brown; externally, the hairs are also yellow, excepting
      on the fore part, where they are dusky brown. The hairs of the
      moustaches are very long and numerous; black at the base, and
      grayish at the apex. The feet are well clothed with hairs which
      cover and nearly hide the claws; the under side of the tarsus is
      clothed with grayish brown hairs. The tail is well clothed with
      tolerably long hairs which completely hide the scales. The hairs
      on the back are of a deep gray colour at the base, broadly
      annulated with yellow near the apex, and dusky at the apex: the
      longer hairs are black: on the throat and belly the hairs are deep
      gray at the base, and broadly tipped with pale yellow—towards the
      cheeks and sides of the body with a deeper yellow. The incisors
      are yellow.

                                                              In. Lines.
 Length    from nose to root of tail                            6      5
           of tail                                              3     3½
           from nose to ear                                     1      4
           of tarsus (claws included)                           1     4¼
           of ear                                               0      7


  Habitat, Patagonia, (_April and January_).


In the arched form of the head this little animal bears considerable
resemblance to a young rabbit, a resemblance which has struck almost all
who have seen it, I have therefore applied to it the specific name
_Cuniculoïdes_. The skull is figured in Plate 33, fig. 2. _a._, its
dimensions are as follows:—

                                                              In. Lines.
 Total     length                                               1      4
 Width                                                          0     10
 Length    of nasal bones                                       0      7
           of incisive foramina                                 0     4¾
 Distance between the outer surface of the incisors and the
   front molar upper jaw                                        0      5
 Longitudinal extent of the three molars of the upper jaw       0     3¾
 Length    of a ramus of the lower jaw, without the incisor     0     9¾

The molar teeth of the upper jaw are figured in Plate 33, fig. 2, _c._
and 2, _e_; of the lower jaw, fig. 2, _d_. Fig. 2, _b_, represents the
incisors of the upper jaw magnified. Fig. 21, _a_, Plate 34, represents
the skull, viewed from beneath, fig. 21, _b_, is the side view of the
same, and fig. 21, _c_, is the lower jaw.

“Specimens were procured at Port Desire, St. Julian, and Santa Cruz; at
this latter place they were caught in numbers, (in traps baited with
cheese,) both near the coast and on the interior plains. A specimen from
Santa Cruz weighed 1336 grains. In the early part of January, there were
young individuals at Port St. Julian.”—D.


                         2. REITHRODON TYPICUS.

  Reithrodon typicus, _Waterh._, Proceedings of the Zoological Society
  of London for February 1837, p. 30.

  _R. vellere suprà pilis flavescenti-fuscis et nigrescentibus
    intermixtis composito; regione circa oculos, genis, lateribusque
    corporis auratis, pilis pallidè fuscis intermixtis; partibus
    inferioribus auratis; rhinario ad latera flavescenti-albo; auribus
    magnis, intùs pilis flavis, extùs flavis et fuscis, indutis; caudâ
    suprà pallidè fuscâ, subtùs sordidè albâ; pedibus albis._

  DESCRIPTION.—Ears large; tarsi moderate; fur moderately long; general
      tint of the upper parts brown—of the upper surface of the head
      blackish; on the cheeks and flanks a rich yellow tint prevails;
      the under parts of the head and body are bright yellow; the feet
      are white; the tail is brownish above and dirty white beneath. The
      ears are tolerably well clothed with hairs, and these are of a
      yellowish colour, excepting on the fore part, externally, where
      they are brown; the tarsi are covered beneath with grayish brown
      hairs; the hairs of the moustaches are numerous and moderately
      long, black at the base and grayish at the apex. The hairs of the
      back are deep gray at the base, broadly annulated with yellow near
      the apex, and black at the apex; on the upper surface of the head
      the hairs are very narrowly annulated with yellow, hence a
      blackish hue prevails. The longer hairs on the back are black; the
      hairs of the throat and belly are gray at the base, and broadly
      tipped with yellow. The incisors are yellow.

                                                              In. Lines.
 Length    from nose to root of tail                            6      0
           of tail                                                 ?[26]
           from nose to ear                                     1     4½
           of tarsus (claws included)                           1     2½
           of ear                                               0     8½


  Habitat, Maldonado, La Plata, (_June_).


This species is of a darker colour than the last, its ears are much
larger and the tarsi are shorter. It has the same rabbit-like
appearance. The molar teeth of the lower jaw are figured in Plate 33,
fig. 4, _a_.

“This mouse, when alive, from its very large eyes and ears, had a
singular appearance, somewhat resembling that of a little rabbit. It
frequents small thickets in the open grassy savannahs near Maldonado,
and was caught with facility by means of traps baited with cheese.”—D.


                     3. REITHRODON CHINCHILLOIDES.
                              PLATE XXVII.

  _R. vellere longissimo et mollissimo; corpore suprà et ad latera
    cinereo, flavescenti-fusco lavato, subtùs flavescenti-albo; caudâ
    corpore breviore, suprà fuscâ, subtùs albâ: auribus parvulis: tarsis
    mediocribus._

  DESCRIPTION.—Ears small; tail shorter than the body; tarsus moderate;
      fur long and extremely soft. General hue of the upper parts of the
      head and body ashy-brown; the lower part of the cheeks and sides
      of the body are of a delicate yellow colour; the under parts of
      the head and body and the rump are cream colour. The ears are
      blackish;[27] the tail is tolerably well clothed with longish
      hairs, which are, however, not so thickly set as to hide the
      scales—on the upper side they are blackish brown; on the sides and
      beneath they are white. The feet are white. All the fur is of a
      deep gray colour at the base; the hairs of the back are of a very
      pale yellow colour (almost white) near the tip, and brown at the
      tip; the longer hairs are black at the apex. The incisors are
      yellow; the hairs of the moustaches are numerous and very
      long—some of them are whitish, and others are black at the root,
      and gray at the apex.

                                                              In. Lines.
 Length    from nose to root of tail                            5      0
           of tail                                              2      4
           from nose to ear                                     1      2
           of tarsus (claws included)                           1      0
           of ear                                               0     5½


  Habitat, South shore of the Strait of Magellan, near the Eastern
  entrance.


This little animal was preserved in spirit, and has since been mounted,
it is probable, therefore, that the colours have been slightly changed.
It is of a smaller size than either of the preceding species. Its fur is
long, extremely soft, and somewhat resembles that of the Chinchilla. The
ears are smaller, and the tail is shorter, and less densely clothed with
hairs than in _Reithrodon cuniculoides_. The skull (see Plate 43, fig.
20, _a_, 20, _b_, and 20, _c_,) differs in many respects from that of
the species last mentioned. It is of a smaller size, the nasal portion
is proportionately shorter and narrower, the incisive foramina are
shorter; the pterygoid processes do not approximate so nearly at their
base, and the pterygoid fossæ are very shallow, whereas in _R.
cuniculoides_ they are deep. In the skull of the animal just mentioned
there are two distinct longitudinal grooves on the palate, which extend
backwards from the incisive foramina, and terminate in two rather large
and deep excavations: these excavations are in the palatine bone, and
situated between the last molar teeth; they are separated from each
other by a narrow, longitudinal, elevated ridge; a narrow ridge also
separates them from the pterygoid fossæ. At the bottom of each of these
hollows are several minute foramina, and in front of them there are two
larger longitudinal foramina. In _R. chinchilloides_, the longitudinal
grooves on the palate and the posterior hollows are shallow, and
consequently much less distinct; the pterygoid fossæ are very nearly on
the same plane as the palate, and are indicated only by a very slight
depression. The incisor teeth are broader than in _R. chinchilloides_,
and the molar teeth are proportionately smaller. The thin plate which
forms the anterior root of the zygomatic arch is deeply emarginated in
front in _R. cuniculoides_ (see Plate 34, fig. 21, _b._); but in _R.
chinchilloides_, the anterior margin of this plate is nearly straight,
(see Plate 34, fig. 20, _c._)

In the form of the lower jaw of the two animals under consideration
there are differences which will be more clearly understood upon
comparing the figures. I will therefore merely notice one remarkable
character which is found in _R. cuniculoides_, and that is, that the
condyloid process is rather deeply concave on the inner side, a
character which does not exist in _R. chinchilloides_, nor do I
recollect having observed it in any other Rodent.

The principal dimensions of the skull of _R. chinchilloides_, are as
follows:—

                                                              In. Lines.
 Total     length                                               1      2
 Width                                                          0     8½
 Length    of nasal bones                                       0     6⅓
           of incisive foramina                                 0      4
 Distance between the outer surface of the incisors and the
   first molar tooth, upper jaw                                 0     4½
 Longitudinal extent of the three molars of the upper jaw,
   taken together                                               0     2¾
 Length    of a ramus of the lower jaw without the incisor      0      8

_General Observations upon the foregoing Species of Muridæ._

In the foregoing descriptions I have endeavoured to convey an idea of
the characters of the species of mice submitted to me for examination
and description, by Mr. Darwin: there are, however, some points upon
which I have been silent in my descriptions. I allude to the characters
observable in the dentition. I have omitted to notice the various
modifications in the structure of the molar teeth, because I found it
would lengthen the descriptions to no good purpose, inasmuch as of
almost all the species I have made outlines of the molars, which will
convey a more clear idea than any verbal description can do.

Upon an inspection of the Plates, it will be seen, that by far the
greater portion of the teeth figured, may be referred to one particular
type of form or pattern, and that this pattern does not agree with that
observed in the molars of _Mus Rattus_, _M. decumanus_, or _M.
musculus_, whilst these three species agree essentially with each other.

In the young Black Rat (_Mus Rattus_), before the teeth are worn, the
two anterior molar teeth, on either side of the upper jaw, present three
longitudinal rows of tubercles, a central series of larger tubercles,
and on each side of these, a row of smaller ones. The front molar has
three of the larger tubercles arranged along the middle of the tooth;
three smaller ones on the outer side, and two, on the inner side. The
second molars have two central tubercles, two outer, and two inner ones.
The posterior molar is nearly round, the body of the tooth consists of
three principal tubercles, and one small tubercle, situated on the inner
and anterior portion of the tooth.

The corresponding teeth in the young of _Mus bimaculatus_ present a very
different appearance; the molars, instead of having three longitudinal
rows of tubercles, have only two. An idea of the appearance of these
teeth may be formed by removing the inner row of tubercles from the
molars of _Mus rattus_. We should then have, as in _Mus bimaculatus_,
molars of a narrower form, the first tooth presenting six tubercles, the
second, four; and the posterior tooth devoid of the small inner lobe;
the opposing tubercles of each tooth, however, in _M. bimaculatus_, are
of equal size.

The molars of the lower jaw of _Mus bimaculatus_ agree with those of _M.
Rattus_ as to the number of tubercles which they possess; they are,
however, proportionately longer and narrower, and, when a little worn,
these teeth, as well as those of the upper jaw, differ considerably from
those of _M. Rattus_. In the last named animal, when the molars are
slightly worn, the ridges of enamel run completely across the tooth, as
in Figs. 18 and 19, Plate 34. Such is not the case in _M. bimaculatus_
at any age. As soon as the molar teeth are worn, the folds of enamel
penetrate the body of the tooth on each side, and those of one side
alternate with those of the other,—in fact, they very nearly resemble
those of the _Hamsters_ (_Cricetus_).

I have selected the molar teeth of _Mus Rattus_ and _M. bimaculatus_ for
comparison, since I happened to possess specimens displaying both the
young and adult states of each. But had I selected, on the one hand,
almost any of the species brought from South America by Mr. Darwin, and,
on the other hand, the _Mus musculus_ or _M. decumanus_, I should have
had to point out the same distinctions—the former agreeing in dentition
with _M. bimaculatus_, and the latter with _M. Rattus_.

The differences pointed out, between the molar teeth of _Mus Rattus_ and
those of _M. bimaculatus_, I cannot but consider as important, since all
the Old World species of _Mus_ which I have yet had an opportunity of
examining (and they are numerous) agree essentially with the former,
whilst the only _Mus_ from S. America (excepting _M. Musculus_ and _M.
decumanus_, which are carried in ships to all parts of the world) in
which I have as yet found molar teeth like those of _M. Rattus_, is the
_Mus Maurus_, and this it has been stated is possibly a variety of _M.
decumanus_.

Although as yet I have not met with species in the Old World possessing
the characters of the South American _Muridæ_, among those of North
America, several have come under my observation. The _Mus leucopus_,
_Symidon hispidum_, and the species of _Neotoma_ certainly belong to the
same group,[28] as does also the species of the Galapagos Islands,
described in this work under the name _Galapagoensis_.

These considerations have induced me to separate the South American mice
from those of the Old World,—or rather from that group of which _M.
decumanus_ may be regarded as the type,—and to place them, together with
such North American species as agree with them in dentition, in a new
genus bearing the name _Hesperomys_.[29]

Whether this group be confined to the Western hemisphere or not, I will
not venture to say, but I think I may safely affirm that that portion of
the globe is their chief metropolis.

The species of the genus _Hesperomys_, which depart most from the
type—whose dentition is least like figs. 5, _a_, and 5, _b_, Plate 33.,
or 6, _a_, and 6, _b_, of the same Plate—recede still farther from the
genus _Mus_, and approach more nearly (as regards the dentition) to the
_Arvicolidæ_. Among the species here described I may mention as
examples, _M. griseo-flavus_, _M. zanthopygus_, and _M. Darwinii_;—see
the molar teeth figured in Plate 34. figs. 15, 16, and 17,—and among the
North American species, those constituting the genus _Neotoma_. The
latter make by far the nearest approach to the _Arvicolidæ_ of any which
have yet come under my observation, not only in the dentition, but in
the form of the skull and the large size of the coronoid process of the
lower jaw; there is, nevertheless, a tolerably well marked line of
distinction between the crania of the _Arvicolidæ_ and _Neotoma_.

The skulls of the animals belonging to the genera _Castor_, _Ondatra_,
_Arvicola_, _Spalax_, and _Geomys_, which constitute the principal
groups of the family _Arvicolidæ_, when compared with those of the
family _Muridæ_, present, among others, the following distinctive
characters.

The temporal _fossæ_ are always much contracted posteriorly, by the
great anterior and lateral development of the temporal bones; the plane
of the intermolar portion of the palate is below the level of the
anterior portion; the coronoid process of the lower jaw is very large,
the articular portion of the condyloid process is proportionately broad;
the descending ramus, or posterior coronoid process, is so situated that
its upper portion terminates considerably above the level of the crowns
of the molars; this same process is generally[30] directed outwards from
the plane of the horizontal ramus. The incisor teeth of the _Arvicolidæ_
differ from those of the _Muridæ_ in being proportionately broader and
less deep from front to back—they are not laterally compressed as in
_Mus_. The molar teeth are rootless,[31] and the folds of enamel are the
same throughout the whole length of the tooth; whereas in _Mus_ they
enter less and less deeply into the body of the tooth as we recede from
the crown, and towards the base of the visible portion (the tooth being
in its socket) the indentations of the enamel are obliterated.

Now in the species of _Hesperomys_, the molar teeth are always rooted,
and in the form of the skull and the lower jaw they agree with the
_Muridæ_, and do not present the characters above pointed out as
distinguishing the _Arvicolidæ_, and as regards the cranium and lower
jaw, it is only in the genus _Neotoma_ that any approach is evinced.

Of the various groups of the order _Rodentia_ found in South America,
the _Sciuridæ_, so far as I am aware, are chiefly confined to the more
northern parts, and do not occur in the most southern; the _Myoxidæ_,
_Gerboidæ_, and _Arvicolidæ_ are wanting. The species of the family
_Muridæ_ belong to different sections to those of the Old World. Of the
_Leporidæ_ I am acquainted only with one well established species—the
_Lepus Braziliensis_, which however is not found “in tota America
Australi,” as Fischer says, there being no Hare yet found in the more
southern parts, where the _Cavies_ and _Chinchillas_ appear to take
their place. The remaining South American Rodents—certain species of
_Hystricidæ_, the genera, _Echimys_, _Dasyprocta_, _Cælogenys_ and
_Myopotamus_, together with the _Octodontidæ_ and _Chinchillidæ_, all
possess a peculiar form of skull and of the lower jaw, (more or less
approaching to figs. 1, Plate 33, and figs. 23, Plate 34.) which I have
described in the “Magazine of Natural History,” for February 1839, and
which is rarely found in the North American, or Old World Rodents. In
enumerating the above groups, I omitted the _Caviidæ_, because in the
form of the lower jaw they differ somewhat from the rest—they possess,
in fact, a form of lower jaw peculiar to themselves; but in the
Chinchillas[32] the transitions between one form and the other are
found.

The South American _Muridæ_, which form the chief part of Mr. Darwin’s
collection, were none of them procured further north than latitude 30°,
with the exception of those from the Galapagos Archipelago. The species
occur at the following localities.

                    WEST COAST OF SOUTH AMERICA.

                      GALAPAGOS ARCHIPELAGO.

                    Mus Jacobiæ.
                    —— Galapagoensis.

                      COQUIMBO.

                    Mus longipilis.
                    —— Renggeri.
                    —— Darwinii.

                      VALPARAISO.

                    Mus Renggeri.
                    —— _decumanus_.

                      CONCEPCION.

                    Mus longicaudatus.

                      CHILOE AND CHONOS ARCHIPELAGO.

                    Mus brachiotis.



                    EAST COAST OF SOUTH AMERICA.

                      MALDONADO.

                    Mus _decumanus_.
                    —— maurus.
                    —— _Musculus_.
                    —— tumidus.
                    —— nasutus.
                    —— obscurus.
                    —— arenicola.
                    —— bimaculatus.
                    —— flavescens.
                    Reithrodon typicus.

                      BUENOS AYRES.

                    —— Mus _decumanus_.

                      BAHIA BLANCA.

                    Mus Braziliensis.
                    —— elegans.
                    —— gracilipes.

                      RIO NEGRO.

                    Mus griseo-flavus.

                      PORT DESIRE.

                    Mus canescens.

                      ST. JULIAN.

                    Reithrodon cuniculoïdes.
                    —— xanthopygus.
                    Reithrodon cuniculoïdes.

                      SANTA CRUZ.

                    Mus canescens.
                    —— micropus.
                    —— xanthopygus.
                    Reithrodon cuniculoïdes.

                      FALKLAND ISLANDS.

                    Mus _decumanus_.
                    —— _Musculus_.

                      STRAITS OF MAGELLAN.

                    Mus xanthorhinus.
                    —— Magellanicus.
                    Reithrodon chinchilloïdes.




                          SECTION—HYSTRICINA.
                              FAMILY— ——?


                           MYOPOTAMUS COYPUS.
                       Myopotamus Coypus, _Auct._

“This animal, in Chile, is known by the name of “Coypu;” at Buenos
Ayres, where an extensive trade is carried on with their skins, they are
improperly called ‘nutrias,’ or otters. In Paraguay, according to Azara,
their Indian name is ‘guiya.’ On the east side of the continent they
range from Lat. 24° (Azara) to the Rio Chupat in 43° 20′;—distance of
1160 miles. This latter river is 170 miles south of the Rio Negro, and
the intervening space consists of level, extremely arid, and almost
desert plains, with no water, or at most one or two small wells. As the
Coypu is supposed never to leave the banks of the rivers, and being,
from its web-feet and general form of body, badly adapted for travelling
on land, its occurrence in this river is a case, like so many others in
the geographical distribution of animals, of very difficult explanation.
The same remark is indeed applicable, but with less force, to its
existence in the Rio Negro. On the west coast, it is found from the
valleys of central Chile (Lat. 33) to 48° S., or perhaps even somewhat
farther, but not in Tierra del Fuego. So that, on the Atlantic side of
the continent, the plains of Patagonia check its range southward, as, on
the Pacific side, the deserts of Chile do to the north. Its range,
including both sides, is from 24° to 48°, or 1440 miles. In the Chonos
Archipelago these animals, instead of inhabiting fresh water, live
exclusively in the bays and channels which extend between the
innumerable small islets of that group. They make their burrows within
the forest, a little way above the rocky beaches. I believe it is far
from being a common occurrence, that the same species of any animal
should haunt indifferently fresh water, and that of the open sea. We
shall see that the Capybara is sometimes found on the islands near the
mouth of the Plata; but these cannot be considered as their habitual
station in the same manner as the channels in the Chonos Archipelago are
to the Coypu. The inhabitants of Chiloe, who sometimes visit this
Archipelago for the purpose of fishing, state that these animals do not
live solely on vegetable matter, as is the case with those inhabiting
rivers, but that they sometimes eat shell-fish. The Coypu is said to be
a bold animal, and to fight fiercely with the dogs employed in chasing
it. Its flesh when cooked is white and good to eat. An old female
procured (January) amongst these islands, weighed between ten and eleven
pounds.” D.




                          FAMILY—OCTODONTIDÆ.


                         CTENOMYS BRAZILIENSIS.

  Ctenomys Braziliensis, _De Blainville_, Bulletin de la Société
  Philomatique, June 1836, p. 62.


  Maldonado, La Plata, (_June_.)


“This animal is known by the name of Tucutuco. I have given an account
of its habits in my journal, but I shall here repeat it for the sake of
keeping together my observations on the less known animals. The Tucutuco
is exceedingly abundant in the neighbourhood of Maldonado, but it is
difficult to be procured, and still more difficult to be seen, when at
liberty. Azara,[33] who has given an account of its habits, with which
every thing I saw perfectly agrees, states that he never was able to
catch more than one, although they are so extremely common. The Tucutuco
lives almost entirely under ground, and prefers a sandy soil with a
gentle inclination; but it sometimes frequents damp places, even on the
borders of lakes. The burrows are said not to be deep, but of great
length. They are seldom open; the earth being thrown up at the mouth
into hillocks not quite so large as those made by the mole. Considerable
tracts of country are completely undermined by these animals. They
appear, to a certain degree, to be gregarious; for the man who procured
my specimens had caught six together, and he said this was a common
occurrence. They are nocturnal in their habits; and their principal food
is afforded by the roots of plants, which is the object of their
extensive and superficial burrows. In the stomach of one which I opened
I could only distinguish, amidst a yellowish green soft mass, a few
vegetable fibres. Azara states that they lay up magazines of food within
their burrows.

“The Tucutuco is universally known by a very peculiar noise, which it
makes when beneath the ground. A person, the first time he hears it, is
much surprised, for it is not easy to tell whence it comes, nor is it
possible to guess what kind of creature utters it. The noise consists in
a short, but not rough, nasal grunt, which is repeated about four times
in quick succession; the first grunt is not so loud, but a little
longer, and more distinct than the three following: the musical time of
the whole is constant, as often as it is uttered. The name Tucutuco is
given in imitation of the sound. In all times of the day, where this
animal is abundant, the noise may be heard, and sometimes directly
beneath one’s feet. When kept in a room, the Tucutucos move both slowly
and clumsily, which appears owing to the outward action of their hind
legs; and they are likewise quite incapable of jumping even the smallest
vertical height. Mr. Reid, who dissected a specimen which I brought home
in spirits, informs me that the socket of the thigh-bone is not attached
by a ligamentum teres; and this explains, in a satisfactory manner, the
awkward movements of their hinder extremities. Their teeth are of a
bright wax yellow, and are never covered by the lips: they are not
adapted to gnaw holes or cut wood. When eating any thing, for instance
biscuit, they rested on their hind legs and held the piece in their fore
paws; they appeared also to wish to drag it into some corner. They were
very stupid in making any attempt to escape; when angry or frightened,
they uttered the Tucutuco. Of those I kept alive, several, even the
first day, were quite tame, not attempting to bite or to run away;
others were a little wilder. The man who caught them asserted that very
many are invariably found blind. A specimen which I preserved in spirits
was in this state; Mr. Reid considers it to be the effect of
inflammation in the nictitating membrane. When the animal was alive, I
placed my finger within half an inch of its head, but not the slightest
notice was taken of it: it made its way, however, about the room nearly
as well as the others. Considering the subterranean habits of the
Tucutuco, the blindness, though so frequent, cannot be a very serious
evil; yet it appears strange that any animal should possess an organ
constantly subject to injury. The mole, whose habits in nearly every
respect, excepting in the kind of food, are so similar, has an extremely
small and protected eye, which, although possessing a limited vision, at
once seems adapted to its manner of life.

“Several species probably will be found to exist south of the Plata. At
Bahia Blanca (Lat. 39°) an animal burrows under ground in the same
manner as the _C. Braziliensis_, and its noise is of the same general
character, but instead of being double and repeated twice at short
intervals, it is single and is uttered either at equal intervals, or in
an accelerating order. I was assured by the inhabitants that these
animals are of various colours, and, therefore, I presume that the two
kinds of noises proceeded from two species. However this may be, they
are extraordinarily numerous: many square leagues of country between the
Sierras Ventana and Guetru-heigue are so completely undermined by their
burrows, that horses in passing over the plain, sink, almost every step,
fetlock deep. At the Rio Negro (Lat. 41°) some closely allied (or same?)
species utters a noise, which is repeated only twice, instead of three
or four times as with the La Plata kind. The sound is, moreover, louder
and more sonorous; and so closely resembles that made in cutting down a
small tree with an axe, that I have occasionally remained in doubt for
some time to which cause to attribute it. Where the plains of Patagonia
are very gravelly (as at Port Desire and St. Julian) the Ctenomys, I
believe, does not occur; but at Cape Negro, in the Strait of Magellan,
where the soil is damper and more sandy, the whole plain is studded with
the little hillocks, thrown up by this destructive animal. It occurs
likewise south of the Strait, on the eastern side of Tierra del Fuego,
where the land is level. Captain King brought home a specimen from the
northern side of the Strait, which Mr. Bennett[34] has called _C.
Magellanicus_: it is of a different colour from the _C. Braziliensis_. I
unfortunately did not make any note regarding the noise of this southern
species: but the circumstance of its existence rather corroborates my
belief in there being several other kinds in the neighbourhood of the
Rio Negro and Bahia Blanca. Otherwise we must believe that the same
animal utters different kinds of noises, in different districts; a fact
which I should feel much inclined to doubt.

“Azara[35] says that the Tucutuco may he ‘found every where; provided
that the soil be pure sand, and the situation not subject to be
overflowed. As these conditions are fulfilled only in certain spots,
their warrens are far separated from each other, even sometimes more
than twenty-five leagues, without it being possible to conceive how
these animals have been able to pass from one place to another.’ The
difficulty, I think, is much overstated; for, as I have said, the
burrows of the Tucutuco are sometimes made in very damp places, near
lakes; so that they certainly might pass over almost any kind of
country. But if the _C. Braziliensis_ and _C. Magellanicus_ be
considered as one species, as some French authors are inclined to do,
then the difficulty will be increased in a very remarkable manner, as we
shall be obliged to transport the Tucutuco over wide plains of shingle,
and across many great rivers, and an arm of the sea.”—D.


                           POEPHAGOMYS ATER.

  Poephagomys ater, _F. Cuvier_, Annales des Sciences Naturelles, 2d
  series, Zoologie, tom. 1. p. 321. June, 1834.


  Chile, (_September_.)


“This animal is generally scarce, but in certain districts, I believe,
of an alpine character, it is abundant. It excavates very extensive
superficial burrows, no doubt, for the purpose of feeding on the roots
of plants, as in the case of the _Ctenomys Braziliensis_, the habits of
which have just been described. Horses passing over districts frequented
by these animals, sink fetlock deep through the turf. I procured my
specimen from Valparaiso, where the country-people called it
‘Cururo.’”—D.


                           OCTODON CUMINGII.

  Octodon Cumingii, _Bennett_, Proc. of Committee of Science and
  Correspondence of the Zool. Soc. for 1832, p. 46.

  —— —— Transactions of the Zoological Society of London, vol. ii. p.
  81. Pl. 16.

  Dendrobius Degus, _Meyen_. Acta Academiæ, c. 1. c. Naturæ Curiosorum,
  xvi. p. 610. Pl. 44, 1833.


  Valparaiso, Chile, (_October_.)


These little animals are exceedingly numerous in the central parts of
Chile. They frequent by hundreds the hedge-rows and thickets, where they
make burrows close together, leading one into another. They feed by day
in a fearless manner; and are very destructive to fields of young corn;
when disturbed, they all run together towards their burrows in the same
manner that rabbits in England do when feeding outside a covert. When
running they carry their tails high up, more like squirrels than rats;
and they often remain seated on their haunches, like the former animals.
According to Molina[36] they lay up a store of food for the winter, but
do not become dormant. The Octodon is the “degu” of that author: he says
that the Indians in past times used to eat them with much relish. These
animals appear to be very subject to be piebald and albinos; as if
partly under the influence of domestication.




                          GENUS—ABROCOMA.[37]


  _Dentes primores ²⁄₂ acuti, eradicati, anticè læves: molares utrinque
    ⁴⁄₄ subæquales, illis maxillæ superioris in areas duas transversales
    ob plicas vitreas acutè indentatus divisis; plicis utriusque lateris
    vix æquè profundis; illis mandibulæ inferioris in tres partes
    divisis, plicis vitreis his internè, semel externè indentatis, areâ
    primâ sagittæ cuspidem fingente, cæteris acutè triangularibus._

  _Artus subæquales._

  _Antipedes 4–dactyli, externo brevissimo, intermediis longissimis et
    ferè æqualibus._

  _Pedes postici 5–dactyli; digito interno brevissimo. Ungues breves et
    debiles, illo digiti secundi lato et lamellari; omnibus setis
    rigidis obtectis._

  _Caput mediocre, auribus magnis, membranaceis; oculis mediocribus._

  _Cauda breviuscula._

  _Vellus perlongum, et molle._

The genus _Abrocoma_ is evidently allied on the one hand to the genera
_Octodon_, _Poephagomys_, and _Ctenomys_, and on the other to the family
_Chinchillidæ_. The four genera just mentioned possess so many
characters in common, that it would be well to unite them, and the name
_Octodontidæ_ may be used to designate the group.

The _Octodontidæ_ appear to bear the same relations to _Echimys_, as the
_Arvicolæ_ do to the _Muridæ_.

In the _Octodontidæ_ the skull is rather short, the inter-orbital space
is broad; the ant-orbital passage is large; the zygomatic arch is thrown
out horizontally from the plane of the palate; the malar bone is broad
and somewhat compressed, and throws up a small post-orbital process; the
glenoid cavity of the temporal bone is narrow; the palate is contracted,
and deeply notched posteriorly, the portion which lies between the molar
teeth descends below the level of the anterior portion; the incisive
foramina are wide: the body of the anterior and posterior sphenoids is
very narrow, and the foramina on either side of them are large: the
occipital condyles are very narrow, widely separated, and the articular
surface is nearly vertical.[38] The descending _ramus_ of the lower jaw
springs from the outer side of the alveolar portion, and terminates in a
point, more or less acute.

The incisors of the upper and lower jaws are of the same width: the
molars are ⁴⁄₄=⁴⁄₄, rootless.

In external characters the species of the present group vary
considerably. The toes are ⁵⁄₅ or ⅘. The claws of the hind feet are
covered by strong, curved bristly hairs.

The principal points of distinction in the external characters of the
four genera under consideration, may be thus expressed.

                               † TOES ⁵⁄₅.

 A. Fore feet formed for burrowing—strong and armed with
      large claws; tail short.
    _a._ Ears minute, incisors very broad                    _Ctenomys_.
    _b._ Ears small, incisors broad                       _Poephagomys_.

 B. Fore feet weak; claws small; incisors narrow; ears
      large.
    _a._ Tail with the apical portion furnished with long
      hair                                                    _Octodon_.


                               †† TOES ⅘.

    _b._ Tail furnished throughout with short adpressed
      hairs                                                  _Abrocoma_.

It is not only in the comparatively small size and weakness of the fore
feet that _Abrocoma_ approaches more nearly to _Octodon_; but it agrees
in having the soles, both of the fore and hind feet (which are devoid of
hair), covered with minute round fleshy tubercles (see the under side of
the tarsus figured in Plate 28.)

In _Octodon_, however, the toes have on their under side transverse
incisions, as the _Muridæ_, and many other Rodents; a character not
found in _Abrocoma_. Here the underside of the toes, like the sole of
the foot, is covered with minute tubercles.

Though in the form of the skull _Abrocoma Cuvieri_[39] agrees most
nearly with that of _Octodon_; it differs in having the anterior portion
narrower and rather larger, compared to the part devoted to the
protection of the brain; the zygomatic arch is shorter, the incisive
foramina are longer, the body of the anterior sphenoid is narrower, and
the auditory bullæ are larger. The principal differences observable in
the form of the lower jaw of _Abrocoma_, when compared with that of
_Octodon_, consists in the coronoid process being smaller, the condyloid
narrower from front to back; the descending _ramus_ more deeply
emarginated posteriorly, and the angle longer and more attenuated.

In those characters in which the skull of _Abrocoma_ departs from that
of _Octodon_, it approaches nearer to _Chinchilla_. In the peculiar form
and large size of the ears, in the extreme softness of the fur, in the
greater development of the pads on the under side of the toes, and in
the possession of only four toes to the fore feet, there are other
points of resemblance between _Abrocoma_ and _Chinchilla_. In the
Chinchilla as well as in _Octodon_ and _Abrocoma_, we find the toe
corresponding to the second (counting from the inner side) furnished
with a broad hollow nail;[40] there are also stiff bristly hairs
covering this nail as in the _Octodontidæ_.

The extreme softness of the fur of the animals about to be described,
suggested for them the generic name of _Abrocoma_. The fur consists of
hairs of two lengths, and the longer hairs are so extremely slender that
they might almost be compared to the web of the spider. The specific
names applied are those of the distinguished naturalists who first made
us acquainted with the two genera, _Octodon_ and _Poephagomys_.


                         1. ABROCOMA BENNETTII.
                              PLATE XVIII.

  Abrocoma Bennettii, _Waterh._, Proceedings of the Zoological Society
  of London, for February 1837, p. 31.

  _A. corpore suprà griseo, ad latera pallidiore et pallidè cervino
    lavato, subtùs albescenti-cervino; gulâ albescenti-griseâ; pedibus
    sordidè albis: auribus amplis, ad marginem posticum rectis, extùs ad
    bases vellere, sicùt in corpore, obsitis: caudâ corpore breviore, ad
    basin crassiusculâ, pilis brevibus incumbentibus vestitâ._

  DESCRIPTION.—Form stout; ears large, with the posterior margin
      straight; fore feet rather small, tarsus short; tail rather
      shorter than the body, thick at the base; fur long and extremely
      soft, and silk-like. General colour pale grayish brown, with a
      slight yellow wash; the upper part of the head and the back dusky
      brown; under parts of the body very pale yellowish brown,
      inclining to white; chin and throat whitish; feet dirty white;
      tail well clothed with hairs, which are closely adpressed, brown
      above, and of a very pale brown beneath at the base, darker
      towards the apex. The hairs of the moustaches are numerous, long,
      rather slender, and of a brownish colour. The ears are brown,
      furnished externally at the base with fur resembling that of the
      body; the remaining parts (both external and internal) are beset
      with long and extremely slender brown hairs, which project
      considerably beyond the margin of the ear. The ordinary fur on the
      back is about ten lines in length, but thickly interspersed with
      this fur, are longer hairs which are so delicate that they may
      almost be compared to the spiders’ thread. Both on the upper and
      under side of the body the fur is deep gray at the base. The
      incisors are yellow.

                                                              In. Lines.
 Length    from nose to root of tail                            9      9
           of tail                                              5      0
           from nose to ear                                     1     11
           of tarsus (claws included)                           1      4
           of ear                                               0     10
 Width     of ear                                               1     0½


  Habitat, Chile, (_August_.)


“This animal was caught amongst some thickets in a valley on the flanks
of the Cordillera, near Aconcagua. On the elevated plain, near the town
of Santa Rosa, in front of the same part of the Andes, I saw two others,
which were crawling up an acacia tree, with so much facility, that this
practice must be, I should think, habitual with them.”—D.


                          2. ABROCOMA CUVIERI.
                              PLATE XXIX.

  Abrocoma Cuvieri, _Waterh._, Proceedings of the Zoological Society of
  London for February 1837, p. 32.

  _Ab. suprà grisea, levitèr ochraceo lavata; abdomine gulâque
    albescenti-griseis; pedibus sordidè albis; auribus amplis, ad
    marginem posticum distinctè emarginatis; caudâ corpore multò
    breviore, et nigrescente._

  DESCRIPTION.—Ears large; tail considerably shorter than the body; fur
      extremely soft; general colour gray faintly washed with yellow;
      under parts of the body grayish white; feet dirty white; tail
      dusky, paler beneath at the base: the ears are large, distinctly
      emarginated behind, and appear to be almost naked, but, upon close
      examination, long and extremely fine hairs may be observed. All
      the fur is gray at the base; the hairs of the moustaches are
      numerous and very long, those nearest the mouth are white, the
      others are black at the base and grayish beyond. The incisors are
      of a palish yellow colour.

                                                              In. Lines.
 Length    from nose to the root of tail                        6      6
           of tail                                              2     10
           from nose to ear                                     1      4
           of tarsi (claws included)                            1      1
           of ear                                               0      7
 Width     of ear                                               0     7½


  Habitat, Chile, (_September_.)


This species is about one-third the size of the last, it differs
moreover in being gray instead of brown, and in having the posterior
margin of the ear emarginated; the tail is also rather shorter in
proportion.

The skull[41] is figured in Plate 33, fig. 1, _a_, and 1, _b_; and fig.
23, _a_, Plate 34. Its length is 1 inch, 4½ lines; width 9¼ lines;
length of nasal bones 6 lines; distance between fore part of incisors
and the front molar (upper jaw) 5 lines; longitudinal extent of the
three molars of upper jaw 3 lines; length of auditory bullæ 5¾ lines;
length of _ramus_ of lower jaw (see Plate 33, fig. 1, _c_,), without
incisors, 11½ lines. Fig. 23, _c_, Plate 34, represents the inner side
of a _ramus_ of the lower jaw: fig. 1, _d_, Plate 33, is the lower jaw
seen from above: fig. 23, _b_, Plate 34, is the same seen from beneath.
This view is given to show the position of the descending ramus of the
lower jaw—that it springs from the outer side of the alveolar portion,
as in a great portion of the South American Rodents, such as
_Dasyprocta_, _Myopotamus_, _Echimys_, _Chinchilla_, and also in that
genus found in the West Indian islands, _Capromys_. Fig. 1, _e_, Plate
33, represents the molar teeth of the upper jaw, and fig. 1, _f_, those
of the lower.

“This species is abundant on the dry hills, partly covered with bushes,
near Valparaiso.”—D.




                          FAMILY—CHINCHILLIDÆ.


                       LAGOSTOMUS TRICHODACTYLUS.

  Lagostomus trichodactylus, _Brooks_, Transactions of the Linnean
  Society, vol. xvi. p. 95, Pl. 9.

  La Vizcache, _Azara_, Essais sur l’Histoire Naturelle des Quadrupedes
  de la Province du Paraguay, vol. ii. p. 41. Trad. Franc.

  Vischacha, _Moyen_, Acta Academiæ, _c. l. c._ Naturæ Curiosorum, Tom.
  xvi. pars 2, p. 584.


  Habitat, La Plata.


“I will not repeat what I have said about the habits of this animal in
my Journal, as it is merely a corroboration of Azara’s account.
According to that author, the Bizcacha is not found north of 30°; and
its southern limit occurs in the neighbourhood of the Rio Negro in 41°.
Where the plains are gravelly, it is not abundant, but (differently from
the _Cavia Patagonica_,) it prefers an argillaceous and sandy formation,
such as that near Buenos Ayres. The Bizcacha abounds over the whole
Pampas, even to the neighbourhood of Mendoza, and there it is replaced
in the Cordillera by an Alpine species. Of the latter animal, I saw one
seated on a pinnacle at a great height, but I could not obtain a
specimen of it. Azara[42] has remarked that the Bizcacha, fortunately
for the inhabitants of Banda Oriental, is not found to the eastward of
the Rio Uruguay; and what makes the case more remarkable is, that
although thus bounded by one river, it has crossed the broader barrier
of the Parana, and is numerous in the province of Entre Rios. I was
assured by a man, whose veracity I can perfectly trust, that these
animals, quasi canes, post coitum adnexi sunt.”—D.




                            FAMILY—CAVIIDÆ.


                            KERODON KINGII.

  Kerodon Kingii, _Bennett_, Proceedings of the Zoological Society of
  London for 1835, p. 190.


  Habitat, Patagonia.


“The Kerodon is common at intervals along the coast of Patagonia, from
the Rio Negro (Lat. 41°) to the Strait of Magellan. It is very tame, and
commonly feeds by day: it is said to bring forth two young ones at a
birth. At the Rio Negro it frequents in great numbers the bottoms of old
hedges: at Port Desire it lives beneath the ruins of the old Spanish
buildings. One old male killed there weighed 3530 grains. At the Strait
of Magellan, I have seen amongst the Patagonian Indians, cloaks for
small children made with the skins of this little animal; and the Jesuit
Falkner says, that the people of one of the southern tribes, take their
name from the number of these animals which inhabit their country. The
Spaniards and half-civilized Indians, call the Kerodon, ‘conejos,’ or
rabbit; and thus the mistake has arisen, that rabbits are found in the
neighbourhood of the Strait of Magellan.”—D.


                            1. CAVIA COBAIA.
                         Cavia Cobaia, _Auct._


  Habitat, Maldonado, La Plata, (_June_.)


“This animal, known by the name of Aperea, is exceedingly common in the
neighbourhood of the several towns which stand on the banks of the Rio
Plata. It frequents different kinds of stations,—such as hedge-rows made
of the Agave and Opuntia, or sand hillocks, or again, marshy places
covered with aquatic plants;—the latter appearing to be its favourite
haunt. Where the soil is dry, it makes a burrow; but where otherwise, it
lives concealed amidst the herbage. These animals generally come out to
feed in the evening, and are then tame; but if the day be gloomy, they
make their appearance in the morning. They are said to be very injurious
to young trees. An old male killed at Maldonado, weighed 1 lb. 3 oz. In
all the specimens I saw there, (during June, or winter,) I observed,
that the hair was attached to the skin less firmly than in any other
animal I remember to have seen.”—D.


                         2. CAVIA PATACHONICA.

  Cavia Patachonica, _Shaw_, General Zoology, vol. ii., part 1, p. 226.

  Dasyprocta Patachonica, _Desmarest_, Mamm. p. 358, Sp. 574.

  Dolichotis —— —— —— —— in Note, p. 359–360

  Chloromys Patachonicus, _Lesson_, Manuel de Mammalogie, p. 301.

  Lièvre Pampa, _Azara_, Essais sur l’Histoire Naturelle des Quad. de la
  Province du Paraguay. French Translation, vol. ii. p. 51.

In the form of the cranium, and in the structure of the teeth, this
animal possesses all the characters of the Cavies (_Caviidæ_).[43]


  Habitat, Patagonia.


“This animal is found only where the country has rather a desert
character. It is a common feature in the landscape of Patagonia, to see
in the distance two or three of these Cavies hopping one after another
in a straight line over the gravelly plains, thinly clothed by a few
thorny bushes and a withered herbage. Near the coast of the Atlantic,
the northern limit of this species is formed by the Sierra Tapalguen, in
latitude 37° 30′, where the plains rather suddenly become greener and
more humid. The limit certainly depends on this change, since near
Mendoza, (33° 30′.) four degrees further northward, where the country is
very sterile, this animal again occurs. Azara erroneously supposed that
its northern range was only 35°.[44] It is not clear on what
circumstances its limit southward between Ports Desire and St. Julian
(about 48° 30′.) depends; for there is in that part no change in the
features of the country. It is, moreover, a singular circumstance, that
although the Cavy was not seen at Port St. Julian during our voyage, yet
Capt. Wood, in 1670, speaks of them as being numerous there. What cause
can have altered, in a wide, uninhabited, and rarely visited country,
the range of an animal like this?

“Azara states,[45] that the Cavy never excavates its own burrow, but
uses that of the Bizcacha. Wherever this animal is present, without
doubt this is true; but on the sandy plains of Bahia Blanca, where the
Bizcacha is not found, the Spaniards maintain that the Cavy is its own
workman. The same thing occurs with the little owls of the Pampas
(_Noctua cunicularia_), which have been described by travellers as
standing like sentinels at the mouths of almost every burrow; for in
Banda Oriental, owing to the absence of the Bizcacha, these birds are
obliged to hollow out their own habitations. Azara says, also, that this
Cavy, except when pressed by danger, does not enter its burrow; on this
point I must again differ from that high authority. At Bahia Blanca I
have repeatedly seen two or three of these animals sitting on their
haunches by the mouths of their holes, which they quietly entered as I
passed by at a distance. Daily, in the neighbourhood of these spots, the
Cavies were abundant: but differently from most burrowing animals, they
wander, commonly two or three together, to miles or leagues from their
home; nor do I know whether they return at night. The Cavy feeds and
roams about by day; is shy and watchful; seldom squats after the manner
of a hare; cannot run very fast, and, therefore, is frequently caught by
a couple of dogs, even of mixed breed. Its manner of running more
resembles that of a rabbit than of a hare. The Cavy generally produces
two young ones at a birth, which are brought forth within the burrow.
The flesh, when cooked, is very white; it is, however, rather tasteless
and dry. Full grown animals weigh between twenty and twenty-six
pounds.”—D.


                         HYDROCHŒRUS CAPYBARA.
                     Hydrochœrus Capybara, _Auct._

“These animals are common wherever there are large rivers or lakes, over
that part of the South American Continent which lies between the Orinoco
and the Plata, a distance of nearly 1400 miles. They are not generally
supposed to extend south of the Plata; but as there is a Laguna
Carpincho (the latter being the provincial name of the Capybara) high up
the Salado, I presume they have sometimes been seen there. Azara does
not believe they ever frequent salt water; but I shot one in the Bay of
Monte Video; and several were seen by the officers of the Beagle on the
Island of Guritti, off Maldonado, where the water is very nearly as salt
as in the sea. The one I shot, at Monte Video, was an old female; it
measured from tip of snout to end of stump-like tail, 3 feet 8½ inches,
and in girth 3 feet 2 inches. She weighed 98 pounds. I opened the
stomachs of a couple, which I killed near a lake at Maldonado, and found
them distended with a thin yellowish green fluid, in which not more than
a trace of a vegetable fibre could be distinguished: it is in accordance
with this fact, that a part of the œsophagus is so narrow, as I am
informed by Mr. Owen, that scarcely anything larger than a crow-quill
can be passed down it. The shape of the dung of these animals is a short
straight cylinder, rounded at the extremities; when dried and burnt, it
affords a pleasant smell like that from cedar wood. These animals do not
burrow holes, but live amongst the thickets, or beds of rushes near
rivers and lakes. At Maldonado they often may be seen during the day,
seated on the grassy plain in small groups of three and four, at the
distance of a few yards from the border of the lake, which they
frequent. I must refer the reader for a few more details respecting
their habits, to my Journal of Researches.—D.”




                           SECTION—LEPORINA.




                            FAMILY—LEPORIDÆ.


                          LEPUS MAGELLANICUS.

  Lepus Magellanicus, _Lesson et Garnot_, Zoologie du Voyage autour du
  Monde de la Corvette, La Coquille.

“A black variety of the domesticated species, which was turned out on
these islands by the earlier colonists, has been considered, but with
some hesitation, by M. Lesson, as a distinct species. He has called it
_Lepus Magellanicus_, and has given the following specific
character,—‘_Pilis omnino atro-violaceis, albis passim sparsis:
auriculis fuscis, capite brevioribus; maculâ albâ naso, interstitio
narium, menti, gulæ, frontique._’[46] In the specimens preserved on
board the Beagle, the form and position of the white marks neither agree
with M. Lesson’s description, nor with each other. In one there is a
broad white patch on one side of the head, and another on one of the
hinder thighs. The Spaniards employed in hunting wild cattle, (who are
all excellent practical observers) assured me, that the black rabbits
were only varieties of the common gray kind, and they gave the following
reasons for thinking so;—namely, that the two sorts did not live apart;
that the black one had not a different range from the other; that the
two bred freely together, and that they produced piebald offspring. As
the rabbits extend their range very slowly, (not having yet crossed the
central range,) the Spaniards have sometimes carried a few and turned
them out in different parts of the island, and thus they have
ascertained that the black and gray kinds breed together freely.
Bougainville, moreover, who visited the part of the island, where the
black variety is now most common, distinctly states, in his voyage round
the world, that no animal, excepting the great wolf-like fox inhabited
these islands. M. Lesson supposes that the _Lepus Magellanicus_ is found
near the Strait of Magellan; but I inquired of the Indians, who live
there, and they knew of no other ‘conejos’ or rabbits, except the
_Kerodon Kingii_, which no doubt is the animal alluded to by the early
voyagers.”—D.


                          1. DASYPUS HYBRIDUS.
                       Dasypus hybridus, _Auct._

“This species seems to prefer rocky and slightly undulating ground, and
hence is common in Banda Oriental and Entre Rios. Azara says it is found
from 26° 30′, to at least 41° south; but, I was assured, perhaps
incorrectly, that the Sierra Tapalguen (37° 30′), where the nature of
the country becomes slightly different, is its southern limit. The _D.
villosus_, _minutus_, and _mataco_, are found at Bahia Blanca, in
latitude 39°. I was also assured that these three species, together with
the _D. hybridus_, frequent the plains near Mendoza, in latitude 33° to
34°.”—D.


                          2. DASYPUS MINUTUS.
                        Dasypus minutus, _Auct._

“The northern limit of this species on the Atlantic side of the
continent, is (as I was told by the inhabitants) near the southern one
of the _D. hybridus_, namely, 37° 30′. It is extremely abundant on the
arid plains near the Sierra Ventana, and likewise in the neighbourhood
of the Rio Negro. This species has a range considerably further
southward than any other: I obtained specimens at Port Desire, where,
however, it is far from common, and at Santa Cruz (in latitude 50°) I
saw its tesselated covering lying on the ground. At Bahia Blanca, I
found in the stomach of this armadillo, coleoptera, larvæ, roots of
plants, and even a small snake of the genus Amphisbæna. All the species,
excepting one, wander about by day. At Bahia Blanca, during a morning’s
ride, three or four of the _D. minutus_ generally were met with; but, in
order to secure them, it was necessary to jump off one’s horse as
quickly as possible, otherwise, they would have disappeared by burrowing
in the sandy soil. This species often endeavours to escape detection by
squatting close to the ground, and remaining motionless.”—D.


                          1. DIDELPHIS AZARÆ.
                        Didelphis Azaræ, _Auct._

“This species is said to inhabit burrows: it is nocturnal, and is very
destructive to poultry. The body after death possesses a very offensive
odour. My specimen was procured at Maldonado.”—D.


                      2. DIDELPHIS CRASSICAUDATA.
                               PLATE XXX.

  Didelphis crassicaudata, _Desmarest_, Nouv. Dict. d’Hist. Nat. 2d Ed.
  ix. p. 425.

  —— —— Mammalogie, p. 257, Species 393.

  Microuré troisième, ou Macrouré à grosse queue, _Azara_, Essais sur
  l’Histoire Nat. des Quad. de la Province de Paraguay, vol. i. p. 284.

  _D. capite brevi; auribus parvis; colore corporis fuscescenti-flavo
    subtùs pallidiore; infra oculos flavescente; caudâ crassâ, caput
    corpusque, quoad longitudinem, ferè æquante; ad basin corporis
    colore tinctâ, dein nigra, ad apicem albâ._

  DESCRIPTION.—Head short; ears small, the posterior edge emarginated
      near the base, distinctly furnished with hairs; tail slightly
      exceeding the body in length, very thick at the base; tarsi small;
      fur moderately long, slightly harsh, and somewhat adpressed (much
      less woolly than in most Opossums): general tint brownish yellow,
      under parts paler; anterior angle of the eye and muzzle brown, the
      tip of the chin, and also the tip of the muzzle on either side
      whitish; on the cheeks, a little below the eyes, is a patch of
      yellow which extends round the angle of the mouth: about one-third
      of the tail is covered with fur of the same colour and character
      as that on the body; beyond this the tail is black, excepting a
      small portion, about one inch in length, at the apex, which is
      white; and the hairs are short, closely adpressed, and scarcely
      hide the scales which are beneath: the fore portion of each foot
      is brown: the hairs covering the ears on the outer side are
      brownish, and those on the inner side of the ear are yellow, but
      towards the outer margin they are brown. The hairs of the back
      have the basal half gray, and the apical half ochreous,
      terminating in yellowish brown; on the belly and underside of
      neck, the hairs are ochreous, faintly tinted with gray at the
      base.

                                                              In. Lines.
 Length    from nose to root of tail                            1      3
           of tail                                             10      3
           from nose to ear                                     2     1½
           of tarsus                                            1     5½
           of ear                                               0      6


  Habitat, Maldonado, La Plata, (_June_).


The species described by Azara, under the name _Macrouré à grosse
queue_, agrees so perfectly with the present animal, that I have no
hesitation in referring it to the _Didelphis crassicaudata_ of
Desmarest, which is founded upon Azara’s description.

The head of the _Didelphis crassicaudata_ is shorter and less pointed
than in most other Opossums; the ears are unusually small, and the tail
is very thick. In the character of the fur also, this species differs
from most others, the hairs being rather short and somewhat adpressed;
and the soft under fur being very scanty. Upon separating the fur on the
back and sides of the body, numerous young hairs were visible in the
specimen from which the above description is taken, and these were of a
bright rusty red tint; the colouring of the animal therefore would, in
all probability, have been very different after a short time, had it not
been killed. Those observed by Azara varied considerably in their
colouring. The skull is figured in Plate 34. figs. 25. Fig. _d_
represents a _ramus_ of the lower jaw.

                                                              In. Lines.
 Length    of the skull                                         2      4
 Width                                                          1      3
 Length    of nasal bones                                       0     9½
 ——        of palate                                            1     2¾
 Width     of palate between the posterior molars               0      5
 Distance between forepart of front incisors and forepart of
   canine                                                       2     0¾
 Distance between forepart of canine and hinder part of last
   molar                                                        1      0
 Length    of _ramus_ of lower jaw (incisors not included)      1    10½

“This specimen was caught at Maldonado: it weighed 14½ oz.”—D.


                         3. DIDELPHIS ELEGANS.
                              PLATE XXXI.

  _D. vellere longo et molli, corpore suprà cinereo-fuscescente lavalo;
    pedibus corporeque subtùs albis, oculis nigra circumdatis,
    interspatio cinerescente; auribus magnis fuscescentibus; caudá,
    capite et corpore, paulo breviore._

  DESCRIPTION.—Muzzle slender and pointed; ears large; tail rather
      shorter than the head and body taken together; fur long and very
      soft: general tint of the upper parts of the head and body ashy
      gray washed with brown; on the sides of the body, especially near
      the shoulders, a faint yellowish tint is observable; the lower
      part of the cheeks, the throat, under parts of the body and the
      feet, are white, with an indistinct yellowish tint; the eyes are
      encircled with brownish black, which tint is extended forwards on
      to the sides of the muzzle; the upper surface of the muzzle and
      the inter-orbital space is pale. The tail is furnished throughout
      with minute decumbent hairs, excepting a small naked space at the
      tip beneath, of about one line in length; on the upper surface
      they are brown, and on the under, they are whitish. The fur of the
      upper and under parts of the body is deep gray at the base; on the
      lower part of the cheeks, chin, and on the mesial line of the
      throat and chest, the hairs are uniform—not gray at the base. The
      ears are brown, and to the naked eye, appear naked.

                                                              In. Lines.
 length    from nose to root of tail                            4      6
           of tail                                              4      4
           of tarsus (claws included)                           0     7½
           from nose to ear                                     1     1½
           of ear                                               0     7¼
 width     of ear                                               0     7½


  Habitat, Valparaiso, Chile, (_October_.)


This little Opossum, which is the only species I am acquainted with from
the west side of the Cordillera, was exhibited at one of the scientific
meetings of the Zoological Society, and its characters were pointed out
by Mr. James Reid, who proposed for it the specific name of
_hortensis_,[47] a name which was given from the circumstance that in
Mr. Darwin’s notes it is stated that a small Opossum was found in a
garden at Maldonado. These notes however refer to the _Didelphis
brachyura_. The skull of this animal is figured in Plate 35. Fig. 5,
_a_, represents the upper side; 5, _b_, the under side; and 5, _c_, is
the side view. Fig. 5, _d_, is the lower jaw, and 5, _e_, is the same
magnified. The length of the skull is 14½ lines; width, 8 lines; length
of palate, 7¼ lines; inter-orbital space, 2½ lines; length of _ramus_ of
lower jaw, 10½ lines. In the palate are two long openings which commence
opposite the posterior false molar, and terminate opposite the hinder
portion of the penultimate true molar: the incisive foramina are nearly
one line in length. On the posterior portion of the palate there are
four other foramina, one on each side near the posterior molar, and one
on either side the mesial line, behind the large palatine openings above
mentioned.

“These little animals frequent the thickets growing on the rocky hills,
near Valparaiso. They are exceedingly numerous, and are easily caught in
traps baited either with cheese or meat. The tail appeared to be
scarcely at all used as a prehensile organ; they are able to run up
trees, with some degree of facility. I could distinguish in their
stomachs the larvæ of beetles.”—D.


                        4. DIDELPHIS BRACHYURA.
                              PLATE XXII.

                      Didelphis brachyura, _Auct._

  _D. vellere brevi, corporis suprà cinereo, flavo lavato; lateribus
    capitis, corporisque, et partibus inferioribus rufescenti-flavis,
    gulâ et abdomine pallidioribus; caudâ brevi._

  DESCRIPTION.—Head large; canine teeth very large; ears rather small;
      tail short; rather more than half the length of the body; fur
      short and crisp; the back and upper surface of the head ashy gray,
      grizzled with yellowish white; the sides of the head and body, and
      under parts rusty yellow, rather paler on the belly than on other
      parts, and of a deeper hue on the rump and cheeks; the eye is
      encircled with rusty yellow; feet yellowish; tail clothed with
      short stiff hairs, and exhibiting scales, brownish above, and
      dirty yellowish white beneath—a small naked space beneath, at the
      tip, of about two lines in length. Fur of the back grayish at the
      base, that on the belly uniform; ears clothed with minute
      yellowish white hairs.

                                                              In. Lines.
 Length    from nose to the root of tail                        6      0
           from nose to ears                                    1      6
           of tail                                              2      8
           of tarsus (claws included)                           0     8¾
           of ear                                               0     3¾


  Habitat, Maldonado, La Plata, (_June_.)


Never having seen a good figure of this animal, I have thought it
desirable to introduce it in the plates of this work.

The _Didelphis brachyura_ is closely allied to the _D. tricolor_ of
authors, but in that species the upper parts of the body are nearly
black; the sides of the head and body are of a deep rusty red tint, and
the under parts are almost white.

“Was caught by some boys digging in a garden. Its intestines were full
of the remains of insects, chiefly ants and others of the Hemipterous
order.”—D.

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

[Illustration:

  _Mammalia Pl. 1._

  _Desmodus D’Orbignyi._
]

[Illustration:

  _Mammalia Pl. 2._

  _Phyllostoma Grayi._
]

[Illustration:

  _Mammalia. Pl. 3._

  _Vespertilio Chiloensis._
]

[Illustration:

  _Mammalia Pl. 4._

  _Canis antarcticus._
]

[Illustration:

  _Mammalia. Pl. 5._

  _Canis Magellanicus._
]

[Illustration:

  _Mammalia Pl. 6._

  _Canis fulvipes._
]

[Illustration:

  _Mammalia Pl. 7._

  _Canis Azaræ._
]

[Illustration:

  _Mammalia Pl. 8._

  _Felis Yagouaroundi._
]

[Illustration:

  _Mammalia Pl. 9._

  _Felis Pajeros._
]

[Illustration:

  _Mammalia Pl. 10._

  _Delphinus Fitz-Royi._
]

[Illustration:

  _Mammalia Pl. 11._

  _Mus longicaudatus._ _Mus gracilipes._
]

[Illustration:

  _Mammalia Pl. 12._

  _Mus bimaculatus._ _Mus elegans._
]

[Illustration:

  _Mammalia Pl. 13._

  _Mus flavescens._ _Mus arenicola._
]

[Illustration:

  _Mammalia Pl. 14._

  _Mus brachiotis._ _Mus Magellanicus._
]

[Illustration:

  _Mammalia Pl. 15._

  _1 Mus Renggeri._

  _2 —— obscurus._
]

[Illustration:

  _Mammalia. Pl. 16._

  _Mus longipilis._
]

[Illustration:

  _Mammalia Pl. 17._

  _Fig. 1 Mus xanthorhinus._ _2 Mus nasutus._
]

[Illustration:

  _Mammalia Pl. 18._

  _Mus tumidus._
]

[Illustration:

  _Mammalia. Pl. 19._

  _Mus Braziliensis._
]

[Illustration:

  _Mammalia Pl. 20._

  _Mus micropus._
]

[Illustration:

  _Mammalia Pl. 21._

  _Mus griseo-flavus._
]

[Illustration:

  _Mammalia Pl. 22._

  _Mus xanthopygus._
]

[Illustration:

  _Mammalia Pl. 23._

  _Mus Darwinii._
]

[Illustration:

  _Mammalia Pl. 24._

  _Mus Galapagoensis._
]

[Illustration:

  _Mammalia Pl. 25._

  _Mus fuscipes._
]

[Illustration:

  _Mammalia Pl. 26._

  _Reithrodon Cuniculcides._
]

[Illustration:

  _Mammalia Pl. 27._

  _Reithrodon Chinchilloides._
]

[Illustration:

  _Mammalia Pl. 28._

  _Abrocoma Bennettii._
]

[Illustration:

  _Mammalia Pl. 29._

  _Abrocoma Cuvieri._
]

[Illustration:

  _Mammalia Pl. 30._

  _Didelphis crassicaudata._
]

[Illustration:

  _Mammalia Pl. 31._

  _Didelphis elegans._
]

[Illustration:

  _Mammalia Pl. 32._

  _Didelphis brachyura._
]

[Illustration:

  _Mammalia Plate 33._

  _G.R. Waterhouse. & C.M. Curtis_
]

[Illustration:

  _Mammalia Plate 34._

  _G.R. Waterhouse_ _J. Swaine_
]

[Illustration:

  _Mammalia Pl. 35._

  _Drawn by C. H. Curtis._
]

-----

Footnote 1:

  The palatine foramina are accidentally omitted—see description.

Footnote 2:

  Voy. Amer. Merid. t. 8.

Footnote 3:

  See his memoir “Sur quelques anomalies du système dentaire dans les
  mammifères,” published in the “Annales Françaises et Etrangères
  d’Anatomie et de Physiologie,” No. 6, pl. IX. fig. 2.

Footnote 4:

  Magazine of Zoology and Botany, No. 12.

Footnote 5:

  “Annales des Muséum d’Histoire Naturelle,” tom. xv. p. 176.

Footnote 6:

  Journal Historique d’un Voyage fait aux Iles Malouines, tom. ii. p.
  459.

Footnote 7:

  Azara has not described this animal, which circumstance alone would
  render it probable that it is not an inhabitant of Paraguay or La
  Plata. The two Foxes mentioned by him are the Aguará-guaza, (_Canis
  jubatus_, Auct.) a very large kind of fox (a strangely exaggerated
  description of this animal is given by Falkner) of which I could not
  obtain a specimen; and the Aguará-chay, or _Canis Azaræ_.

Footnote 8:

  Molina, Compendio de la Historia del Reyno de Chile, vol. i. p. 330
  and 332.

Footnote 9:

  I am indebted to Mr. Ogilby, who visited the Prince’s collection, for
  a description from the specimens of _C. Azaræ_ therein preserved. In
  this description the tip of the tail is said to be black.

Footnote 10:

  Considering the great difference of climate and other conditions
  between the hot and wooded country of Paraguay, and the desolate
  plains of Patagonia, one is led to suspect that the _Canis Azaræ_ of
  La Plata and Patagonia, which wanders about by day, and inhabits
  burrows instead of heaps of straw, may turn out to be a different
  species from the Agouará-chay of Azara, which is nocturnal in its
  habits, and lives in thick coverts.

Footnote 11:

  In measuring the species of Mammalia, I almost invariably, when
  wishing to give the length, measure from the tip of the nose _along
  the curve of the back_ to the root of the tail. In the Ruminantia of
  course this plan is not desirable, but in other Mammals I have found
  it most convenient. If we take a Cat, for instance, and curve the body
  in whatever way we please, we find the length (taken in the way just
  mentioned) always the same. Whereas, if we take a straight line (as
  many naturalists do) the length will vary according to the position of
  the animal.

Footnote 12:

  I must refer the reader to my journal for some account of the habits
  of the jaguar and puma, which being well known animals, and the facts
  that I mention having little scientific interest, I have not thought
  it worth while to repeat them here.

Footnote 13:

  D’Orbigny says, (vol. ii. p. 69,) that all the species of the genus
  have this habit.

Footnote 14:

  Figures 47 and 48 of M. Cuvier’s work represent horns so unlike either
  of those brought over by Mr. Darwin, that I cannot help suspecting
  they belong to some other species of stag.

Footnote 15:

  The MS. name of _M. decumanoïdes_, which I had applied to this animal,
  has been changed, in consequence of my having seen a different
  species, with the same name attached, in the museum of the India
  House.

Footnote 16:

  The great Bandicoot rat of India, (_Mus giganteus_, of Hardwicke,)
  ought, perhaps, to be added to the species above enumerated; and I
  strongly suspect several catalogued species will prove but varieties
  of this animal.

Footnote 17:

  See Proceedings of the Zoological Society for February 14th, 1837, p.
  19.

Footnote 18:

  As I shall have occasion to use the terms _moderate_, _long_, _short_,
  _large_, &c. it may be well to state that I take the common mouse,
  (_Mus Musculus_,) as my standard of comparison. The ears, feet, tail,
  length of the fur, general proportions, &c. are in that animal what I
  term moderate.

Footnote 19:

  A long tarsus is generally accompanied by a proportionately long tail.
  I presume that those Mice which have long tarsi are in the habit of
  making great leaps, and that in these leaps, the tail serves to steady
  and balance the body.

Footnote 20:

  In _Mus leucopus_ of North America the tarsus is hairy beneath, and in
  the character of the teeth this animal also agrees with the species
  above mentioned.

Footnote 21:

  The dimensions given in the Proceedings of the Zoological Society were
  taken from a younger specimen than those here described, and there is
  an error in the length of the tail there given, which should be 1–10
  instead of 2—10.

Footnote 22:

  In _Mus longipilis_ and _M. brachiotis_ may be perceived an approach
  to this elongated form of the muzzle.

Footnote 23:

  I am sorry to say the artist has not drawn this skull with his usual
  fidelity, a circumstance which I did not perceive until it was too
  late to make any alteration: it is too large, and the incisors are
  represented as projecting forwards too much; they are in the original
  so nearly at right angles with the upper surface of the skull that but
  a very small portion of them is seen, when it is viewed, as
  represented at fig. 3, _a_.

Footnote 24:

  It is not easy to measure the _width_ of the ears in these animals:
  upon measuring with a thread over the curve of the outer side I have
  found the width of the ears of the present animal to be as above
  given,—the dimension slightly exceeding that stated in the Proceedings
  of the Zool. Soc.

Footnote 25:

  Ρειθρος, a channel; Οδον, a tooth.

Footnote 26:

  The tail is imperfect.

Footnote 27:

  They are naked, but I suspect the hair has been rubbed off.

Footnote 28:

  I am acquainted with seven North American Species of _Muridæ_, all of
  which possess the dentition of _Hesperomys_.

Footnote 29:

  Ἐσπερος, West, and Μυς.

Footnote 30:

  I am acquainted with only one exception, and that is in the genus
  _Castor_. In the genus _Ondatra_, the descending ramus is but slightly
  twisted outwards, but in all the other _Arvicolidæ_, whose crania I
  have examined, it is remarkably so, and in the genera _Spalax_ and
  _Geomys_, where this character is carried to the extreme, the
  descending ramus projects from the alveolus of the long inferior
  incisors, in the form of a rounded and almost horizontal plate.

Footnote 31:

  In aged individuals of some of the species of _Arvicolidæ_, the molar
  teeth possess short roots. In a skull of _Ondatra_ now before me I
  find all the molars divided at the base into two portions, which in
  all probability would have formed solid roots had the animal lived
  longer.

Footnote 32:

  See Proceedings of the Zoological Society for April 9th, 1839, p. 61.

Footnote 33:

  Azara’s Voyages dans l’Amerique Meridionale, vol. i. p. 324.

Footnote 34:

  Transactions of the Zoological Society, vol. ii. p. 84.

Footnote 35:

  Azara Voyage dans l’Amerique Meridionale, vol. i. p. 324.

Footnote 36:

  Compendio de la Hist. Nat. del Reyno de Chile, vol. i. p. 343.

Footnote 37:

  Ἁβρος, soft; Κομη, hair.

Footnote 38:

  There is a wide difference between the present animals and the
  _Arvicolidæ_ in the form of the occipital condyles: the same
  difference is also observable between _Echimys_ and _Mus_. The
  _Octodontidæ_ in fact have the same form of condyles as the
  Chinchillas and Cavies. In this and many other characters the last
  mentioned animals evince an affinity to the _Leporidæ_.

Footnote 39:

  I have not had an opportunity of examining the skull of _Abrocoma
  Bennettii_.

Footnote 40:

  This nail no doubt is used to cleanse the fur, and the bristly hairs
  may also assist in the operation; the two small toes of the Kangaroo’s
  hind foot are used for the same purpose.

Footnote 41:

  The skull is, unfortunately, imperfect, the hinder portion is injured,
  and the arches which enclosed the ant-orbital openings are broken.

Footnote 42:

  Azara ‘Voyages dans l’Amerique Meridionale,’ vol. i. p. 316.

Footnote 43:

  See Proceedings of the Zoological Society for April, 1839, p. 61.

Footnote 44:

  Azara, Voyage dans l’Amérique Méridionale, vol. i. p. 318.

Footnote 45:

  Azara, Quadrupeds of Paraguay.

Footnote 46:

  Voyage de La Coquille. Partie Zoologique, vol. i. p. 168.

Footnote 47:

  See Proceedings of the Zoological Society of London for January, 1837,
  p. 4.; its characters were not published.

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




                          TRANSCRIBER’S NOTES


 1. Silently corrected obvious typographical errors and variations in
      spelling.
 2. Retained archaic, non-standard, and uncertain spellings as printed.
 3. Enclosed italics font in _underscores_.