MAMMALS. 13 



color at base, then pale cinnamon white to cinnamon. Tail like the back, its tip black, with the hairs light colored at base. 

 Length about 12 inches; tail, wiih hairs, 4 ; hind foot about 2.25 inches. 



This well known marmot we found very abundant throughout Texas, and on the Jornada del 

 Muerto, of New Mexico. We did not observe it north of this district, nor did we find it west 

 of the Bio Grande at all. However, it was found by Mr. Clark, near the copper mines of Santa 

 Rita, and in other places west of the Rio Grande ; but the nature of the country over which we 

 passed was of a nature unsuited to their habits, being too barren, and generally not affording 

 vegetation of the kind upon which they feed. 



GEOMYS CLARKII, Baird. Pecos Gopher. 



Geomys darkii, BAIRD, Pr. A. N. Sc. Ph. VII, April, 1855, 332. IB. Gen. Rep. Mammals, 1857, 383. 



SP. GIF. Upper incisors with a single deep groove bisecting the surface, the portions on either side equal. Fore feet 

 nearly equal to or rather shorter than the hinder ones. Second claw of the hand reaching as far as the fourth. Pouches small. 

 Fur soft and full. 



Color above, uniform yellowish brown, the hairs with dusky tips. Beneath, paler and grayer. Cheek pouches much like the 

 surrounding region. 



A fine specimen of this species was obtained on the Pecos river, Texas. 



THOMOMYS BULBIVORUS, Baird .California Gopher. 



PLATE XI. 



? Diplostoma bulbivorum, RICH. F. B. Am. I, 1829, 206; pi. xviii, B, (marked Diploftoma doiiylassi.) IB. Zool of 



Blossom, 1839, 13. 

 Thomomys btttae, LESSON, Nouv. Man. R. An. 1812, 119. 



BAIRD, Pr A. N. Sc. Phila. VII, April, 1^55, 335. 

 Thomomys bulbivorus, BAIRD, Gen. Rep. Mammals, 1857, 389. 



SP. CH Cheek pouches large, completely furred inside, white to their very margin, which is dark brown, forming a very 

 strong contrast. Tail from one-third to less than one-half the length of body ; slender at base. Upper incisors quite convex 

 transversely; groove obsolete. Hands small; claws very slender and delicate, nearly straight; middle claw 4 lines, its under 

 surface occupying about two -sixths the whole hand, its finger barely shorter than this ; claw of thumb extending over two-fifths 

 of whole hand. 



CoLr. Reddish chestnut brown above and on sides, finely lined everywhere by dusky tips to the hairs, without any uniform 

 dark wash on the back. Beneath paler. Tail grayish white, except a short line of dusky along the base above. Chin dusky; 

 its extremity white. 



This species was observed in various parts of California, especially near San Francisco. 

 THOMOMYS LATICEPS, B a i r d .Broad-headed Gopher. 

 PLATE XII, FIG. 2. 



Thomomys laticeps, BAIRD, Pr. A. N. Sc. Phil. VII, April, 1855, 335. 

 IB Gen. Rep. Mammals, 1857, 392. 



SP. CH. Cheek pouches moderate, well haired. Tail nearly one-half the body, thick at base. Skull very broad and muzzle 

 short ; the upper incisors convex, the groove quite distinct. Feet very large and broad. Claws of fore foot or hand small, 

 slender, 4 lines long above ; below, about two-sevenths the length of the whole hand, its digit about two-eighths. Claw of thumb 

 extending over nearly three-sixths the hand. 



Color. Above, yellow reddish brown; the dorsal region with the hairs largely and sharply tipped with blackish; sides nearly 

 uniform ; beneath, tinged with reddish. Pouches dull white, the dusky of the surrounding region dipping into them. Tail grayish 

 white, dusky above. 



One specimen was obtained by Lieutenant Trowbridge at Humboldt Bay. 



