GEOMYID^E— TIIOMOMYS CLUSIUS. G29 



THOMOMYS CLUSIUS, Coues. 



Rocky Mountain Pocket Gopher. 



Tlionwmya chisinn, Coues, Proc. Phila. Acad. 1875, 138 (descr. orig. Bridger's Pass, Rocky Mountains). — 

 Coues, Powell's Rep. Colorado R. 1875, 263, f. 80 (samo specimen redescribed aud figured). 



Diagnosis. — Smallest known species of the genus. Length ( 9 , 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. Mammae, 6 pairs. 



Habitat. — 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. Hammond. 



