130 Pouched Jirboa Mouse
DIPODOMYS PHILLIPPSII.--GRAY. [[Dipodomys californicus] POUCHED JERBOA MOUSE. [California Kangaroo Rat] PLATE CXXX.--MALES. D. Magnitudine prope Tamiae Lysteri et forma Dipodum; cauda corpore et capite conjunctum multo longiore; sacculis buccalibus externis apertis; colore, supra fulvo, infra albo.
CHARACTERS. Nearly the size of the common ground squirrel (Tamias Lysteri); shaped like the jerboas; tail, much longer than the body; cheek pouches, opening externally; colour, light brown above, white beneath. SYNONYME. DIPODOMYS PHILLIPPSII. Gray, Ann. and Mag. Nat. Hist., vol. vii. p. 521. 1840. DESCRIPTION. Body, rather stout; head, of moderate size; nose, moderate, although the skull exhibits the proboscis extended five or six lines beyond the insertion of the incisors. The whiskers (which proceed from the nose immediately above the upper edge of the orifices of the pouches) are numerous, rigid, and longer than the head; ears, of moderate size, ovate, and very thinly clothed with short hairs; the feet are thickly clothed with short hairs to the nails, which are free; short hairs also prevail on the soles and between the toes; fore feet, rather stout, but short; they have each four toes and the rudiment of a thumb, the latter covered by a conspicuous nail; nails, short, slender, and curved; second toe from the thumb longest, first and third nearly of equal length, and fourth shortest. Hind legs, very long; the hind feet have each four toes, the two middle ones nearly of equal length, the first a little shorter, and the fourth, placed behind like a thumb, much the shortest; nails, nearly straight, sharp pointed, and grooved on the under surface; tail, rather stout--in the dried specimen it is round at base and much compressed, showing that its greatest diameter is vertical; it is thickly clothed with short hairs for two thirds of its extent, when the hairs gradually increase in length till they approach the extremity, at which they are so long as to present the appearance of a tuft-like brush. The fur is very soft and silky, like that of the flying-squirrel; the hairs of the tail are coarser. There are two abdominal and two pectoral mammae. In the upper jaw the incisors are rather small and weak; all the molars have simple crowns, which are more elevated on the interior than on the exterior edges; the anterior molar is nearly round, and almost of the same size as the two next molars, which are somewhat oval and are placed with their longest diameter transversely to the jaw; the fourth molar is the smallest and is nearly round. In the lower jaw the three anterior molars are nearly of equal size, and are almost alike in shape; the fourth corresponding with the last molar on the upper jaw; there is a little depression in the centre of the crowns of the molars, and a slight ridge around the outer edges. COLOUR. Head, ears, back, and a stripe on the thigh from the root of the tail, light brown, the hairs on the back being plumbeous at the roots, then yellow slightly tipped with black. Whiskers, black, with a few white bristly hairs interspersed; upper and lower surfaces of tail, and a line on the under side of the tarsus, dark brown; sides, and tip of the tail, white; cheeks, white; there is a white stripe on the hips; the legs and under surface are white, as also a stripe from the shoulder to the ear. This white colour likewise extends high up on the flanks, where it gradually mingles with the brown of the back; nails, brownish. DIMENSIONS. Male.--Specimen in the British Museum. Inches. Lines. Length of head and body, . . . . . . . . . 5 0 Length of tail, . . . . . . . . . . . . 6 6 Length of hind feet,. . . . . . . . . . . 1 6 Female.--Procured by J. W. AUDUBON in California. Inches. Lines. Point of nose to root of tail, . . . . . . . 4 6 Tail, including hair, . . . . . . . . . . 7 0 Tarsus to end of longest nail, . . . . . . . 1 6 Ear, inside, from auditory opening,. . . . . . 0 7 Longest hair of whiskers, . . . . . . . . . 2 4 HABITS. The pretty colours and the liveliness of this little kangaroo-like animal, together with its fine eyes and its simplicity in venturing near man, of whom it does not seem afraid, would no doubt make it a favourite pet in confinement. It is able to exist in very arid and almost barren situations, where there is scarcely a blade of anything green except the gigantic and fantastic cacti that grow in Sonora and various other parts of Western Mexico and California. As JOHN W. AUDUBON and his party travelled through these countries the Dipodomys Phillippsii was sometimes almost trampled on by the mules, and was so tame that they could have caught the animal by the hand without difficulty. This species hop about, kangaroo fashion, and jump pretty far at a leap. When the men encamped towards evening, they sometimes came smelling and moving about the legs of the mules, as if old friends. One was observed by J. W. AUDUBON just before sunset; its beautiful large eyes seemed as if they might be dimmed by the bright rays which fell upon them as it emerged from a hole under a large boulder, but it frisked gaily about, and several times approached him so nearly, as he sat on a stone, that he could have seized it with his hands without any trouble, and without rising from his hard seat. After a while, as the party had to take up the line of march again, he with some difficulty frightened it, when with a bound or two it reached its hole and disappeared underneath the large stone, but almost immediately came out again; and so great was its curiosity that as the party left the spot it seemed half inclined to follow them. These animals appear to prefer the sides of stony hills which afford them secure places to hide in, and they can easily convey their food in their cheek-pouches to their nests. The young when half grown exhibit the markings of the adults to a great extent. This species is crepuscular if not nocturnal, and was generally seen towards dusk, and occasionally in such barren deserts that it was difficult to imagine what it could get to feed on. A dead one was picked up one day while the party were traversing a portion of the great Colorado desert, where nothing could grow but clumps of cacti of different species, and not a drop of water could be found. The only living creatures appeared to be lizards of several kinds, and one or two snakes: the party felt surprised as they toiled on over the sun-baked clay, and still harder gravel, to find the little animal in such a locality. GEOGRAPHICAL DISTRIBUTION. Dr. J. L. LE CONTE found this species on the river Gila, and farther south, where he procured several specimens. J. W. AUDUBON saw the Dipodomys Phillippsii in crossing the Cordilleras, in Sonora on the Gila, in the Tulare valley, and in various other parts of California. Its southern limits are undetermined, but it seems not to exist north of California. GENERAL REMARKS. Mr. GRAY described this species, in the Annals and Magazine of Natural History, vol. vii. p. 521; he considered it the American representative of the African Jerboas, although, as he remarks, it differs from them in being provided with cheek pouches opening externally. Our drawing was made from a beautiful specimen in the British Museum, which was the first one brought under the notice of naturalists, and the original of Mr. GRAY's description of this singular animal; it was procured near Real del Monte, in Mexico.