GEOMYIDAi—THOMOMYS CLUSIUS. 629 
THOMOMYS CLUSIUS, Coues. 
Rocky Mountain Pocket Gopher. 
Thomomys clusius, Cougs, Proc. Phila. Acad. 1875, 138 (descr. orig. Bridger’s Pass, Rocky Mountains).— 
Cours, Powell’s Rep. Colorado R, 1875, 263, f. 80 (same specimen redescribed and figured). 
Dracnosis.—Smallest known species vf the genus. Length (¢, adult) 
about 5 inches. Feet remarkably small; sole of hind foot, 0.75; palm of 
hand, including longest claw, 0.65. Fore claws small, weak, little curved, the 
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 from 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. Color above pale yellowish-gray, with a 
slight light-brown shade; the fur plumbeous 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. Mammee, 6 pairs. 
THaprrat.—The single specimen of the species at present known, No. 
3051, Museum of the Smithsonian Institution, was taken at Bridger’s Pass, 
Rocky Mountains, July 28, 1857, by Dr. W. A. Hammend. 
