Chapter V: Part 5

_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.

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_Mammalia Pl. 1._

_Desmodus D’Orbignyi._
]

_Mammalia Pl. 2._

_Phyllostoma Grayi._
]

_Mammalia. Pl. 3._

_Vespertilio Chiloensis._
]

_Mammalia Pl. 4._

_Canis antarcticus._
]

_Mammalia. Pl. 5._

_Canis Magellanicus._
]

_Mammalia Pl. 6._

_Canis fulvipes._
]

_Mammalia Pl. 7._

_Canis Azaræ._
]

_Mammalia Pl. 8._

_Felis Yagouaroundi._
]

_Mammalia Pl. 9._

_Felis Pajeros._
]

_Mammalia Pl. 10._

_Delphinus Fitz-Royi._
]

_Mammalia Pl. 11._

_Mus longicaudatus._ _Mus gracilipes._
]

_Mammalia Pl. 12._

_Mus bimaculatus._ _Mus elegans._
]

_Mammalia Pl. 13._

_Mus flavescens._ _Mus arenicola._
]

_Mammalia Pl. 14._

_Mus brachiotis._ _Mus Magellanicus._
]

_Mammalia Pl. 15._

_1 Mus Renggeri._

_2 —— obscurus._
]

_Mammalia. Pl. 16._

_Mus longipilis._
]

_Mammalia Pl. 17._

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

_Mammalia Pl. 18._

_Mus tumidus._
]

_Mammalia. Pl. 19._

_Mus Braziliensis._
]

_Mammalia Pl. 20._

_Mus micropus._
]

_Mammalia Pl. 21._

_Mus griseo-flavus._
]

_Mammalia Pl. 22._

_Mus xanthopygus._
]

_Mammalia Pl. 23._

_Mus Darwinii._
]

_Mammalia Pl. 24._

_Mus Galapagoensis._
]

_Mammalia Pl. 25._

_Mus fuscipes._
]

_Mammalia Pl. 26._

_Reithrodon Cuniculcides._
]

_Mammalia Pl. 27._

_Reithrodon Chinchilloides._
]

_Mammalia Pl. 28._

_Abrocoma Bennettii._
]

_Mammalia Pl. 29._

_Abrocoma Cuvieri._
]

_Mammalia Pl. 30._

_Didelphis crassicaudata._
]

_Mammalia Pl. 31._

_Didelphis elegans._
]

_Mammalia Pl. 32._

_Didelphis brachyura._
]

_Mammalia Plate 33._

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

_Mammalia Plate 34._

_G.R. Waterhouse_ _J. Swaine_
]

_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_.