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Show 264 EXPLORATION OF THE OARONS OF THE OOLORADO. longest under 0.30. Incisors as usual in the genus. Muzzle almost entirely hairy, with a very small naked pad confined between the nostrils. Pouches ample, about 1.75 deep (measured from the beginning of the fold of skin at the side of the snout). Tail extremely short; under 1.50 in length fi·om the true base, and little over 1.00 from the end of the conical enlargement at base; the thinly-haired portion being thus less than one-fourth the total length of head and body. Ears minute. Uolor above pale yellowish-gray, with a slight light-brown shade; the fur plumbcous at base, as usual. Below, nearly pure white, the fur being mostly of this color to the very base. No dark auricular area. Feet and tail white. Extremity of snout blackish. Claws and whiskers colorless. Incisors faced with orange. HAUI'l'AT.-The single specimen of the species at present known, No. 3051, Museum of the Smithsonian Institution, was tal<en at Bridger's Puss, Rocky Mountains, July 28, 1857, by Dr. W. A. llammond. With only one specimen to go upon, there is little to be added to the foregoing diagnosis. That the small size is not due to immaturity i evidenced by the fact that the specimen is a female, with functionally-developed teats, which had been in use. As well as I can determiuc from the dried skin, there are twelve mammre,* situated as in T. talpoides. In its present state, somewhat stretched, the sldn measures about 5~ inches from nose to root of tail. The general dimensions, as well as the relative and absolute length of tail and the proportions of the feet, are all quite beyond the utmost limit of variation determined for any other form of Thomomys. It may give an idea of the smallness of the feet to say that the hind ones are no larger than those of the white-footed mouse (Hespe1·omys leucopus); they nrc a t.riHe broader, but not quite so long. The fore feet are decidedly shorter than 1 he hinder ones, owing to the slight development of the slcncler weak claws. 'l"'IC eans arc minute-IScarcely larger, comparatively, than in a Geomys, though the tiny auricle has the recognizable shape of Thomomy.o;, instead of being a mere tumid rim. The tail, as well as can be guessed from the present dried state, isles~:; than a f(nJrth as long as the head and bony, mcn.Rurcd from its apparent base. All these characters are utterly incompatible wit.h any variety . • '!'his appears to bo tho uormnl number in this gcnuti; but., in un alcoholic specimen of talpoide 8 , w1~h ~~~ fnr nil ~one from tho belly, completely exposing tho pnrts, I can find bnt eight; tho two axillary pairS uOillg WI\Utlllg. .· • |
