110 Mole-shaped Pouched Rat
PSEUDOSTOMA TALPOIDES.--RICH. [Thomomys talpoides] MOLE-SHAPED POUCHED RAT. [Northern Pocket Gopher] PLATE CX.--MALES. P. Magnitudine muris ratti, corpore nigro cinerescente, capite pro portione parvo, mento albo, macula alba ad gulam, pedibus posticis quadridigitatis.
CHARACTERS. Size of the black rat; head, small in proportion; body, grayish-black; chin, white; a white patch on the throat; only four perfect toes on the hind feet. SYNONYMES. CRICETUS (?) TALPOIDES. Rich, Zool. Jour. No. 12, p. 5, pl. 18. ? GEOMYS ? TALPOIDES. Rich, F. B. A., p. 204. OOTAW-CHEE-GOES-HEES. Cree Indians. DESCRIPTION. Body, shaped like that of the mole; head, rather small; nose, obtuse and covered with short hairs; incisors, strong, with flat anterior surfaces; upper ones short and straight, and each marked with a single very fine groove close to their inner edge; lower incisors, long, curved inwards, and not grooved; whiskers, composed of fine hairs as long as the head; eyes, small; auditory opening, small and slightly margined; ears, scarcely visible beyond the fur. The pouches have an opening on the sides of the mouth externally, and are of moderate size; extremities, very short; the fore foot has four toes and the rudiment of a thumb; the middle toe is longest and has the largest claw, the first and third are equal to each other in length, the outer one is shorter and placed far back, and the thumb, which is still farther back, consists merely of a short claw; the fore claws are long, compressed, slightly curved, and pointed; they are, however, less robust than those of some other species of the genus, especially P. bursarius. On the hind feet there are four short toes, armed with compressed claws much shorter than those on the fore feet, and the rudiment of a fifth toe, so small that it can be detected only after a minute inspection; tail, very slender, cylindrical, and rather short, covered with a smooth coat of short hairs. The hair is nearly as fine as that of the common shrew mole, and is close and velvety. COLOUR. Whiskers, black; incisors, yellowish-white, approaching flesh colour; chin and throat, white; outer edges of the pouch, light gray; tail, grayish-brown; the body generally, grayish-black, with faint brownish tints in some lights. DIMENSIONS. Inches. Lines. Length of head and body,. . . . . . . 7 4 Tail to end of hair, . . . . . . . . 2 5 From point of nose to eye, . . . . . . 0 9 From point of nose to auditory opening,. . 1 3 Height of back,. . . . . . . . . . 2 0 Length of lower incisors, . . . . . . 0 5 Length of fur on the back, . . . . . . 0 6 Length of middle fore claw,. . . . . . 0 4 From heel to end of middle hind claw, . . 0 11 HABITS. Very little is known of the habits of this peculiar sand-rat. The manners, however, of all the species of the genus Pseudostoma are probably very similar: they live principally under ground, and leave their galleries, holes, or burrows, pretty much as we of the genus Homo quit our houses, for the purpose of procuring the necessaries of life, or for pleasure, although they do find a portion of their food while making the excavations which serve them as places in which to shelter themselves and bring forth their young. They are generally nocturnal, and in the day time prefer coming abroad during cloudy weather. They never make their appearance, nor do they work in their galleries or burrows during the winter in our northern latitudes, unless it be far beneath the hard frozen ground, which would not permit them to make new roads. RICHARDSON says that as soon as the snow disappears in the spring, and whilst the ground is as yet only partially thawed, little heaps of earth newly thrown up attest the activity of this animal. The specimen from which our figures were made was presented to the Zoological Society by Mr. LEADBEATER, who obtained it from Hudson's Bay. It also served Dr. RICHARDSON for his description: he was inclined to identify it with a small animal inhabiting the banks of the Saskatchewan, which throws up little mounds in the form of mole hills, but generally rather larger; he, however, could not procure any specimens. As an evidence that this animal never feeds upon worms, he mentions the fact that none exist in high northern latitudes. A gentleman who had for forty years superintended the cultivation of considerable pieces of ground on the banks of the Saskatchewan, informed him that during the whole of that period he never saw an earthworm turned up. All the species of Pseudostoma, as far as our knowledge goes, feed on bulbs, roots, and grasses. The pouches serve as sacks, in which after filling them with food they carry it to their nests in their subterranean retreats, where they deposit considerable quantities, which evidently serve them as supplies throughout the winter. We are under the impression that none of the species of this genus become perfectly dormant in winter, as we have observed in Georgia a few fresh hillocks thrown up by the Southern pouched-rat after each warm day in that season. GEOGRAPHICAL DISTRIBUTION. As before stated, this species was obtained at Hudson's Bay, and is supposed by RICHARDSON to exist on the Saskatchewan, thus giving it a considerable western range, should there not indeed prove to be a different species, which is, however, rather probable. GENERAL REMARKS. Until very recently there has been much confusion among writers in regard to the organization of the family of pouched-rats, which appear to be exclusively confined to the American continent--some supposing that the natural position of the pouch was that of a sac hanging suspended on each side of the throat, with the opening within the mouth. For the probable origin of this error we refer our readers to the first volume of this work, p. 338, where we gave some remarks on the Pseudostoma bursarius, and this genus generally.