400 



U. S. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



margin to the auditory aperture. The whiskers are shorter than the head, mixed dusky and 

 gray. The upper incisors are yellow, rather plane in front, with a very obsolete groove near 

 the inner slightly raised edge. The cheek pouches are large, extending backwards at least to 

 the occiput (in the dried specimens) ; densely lined with hair on the side next the jaw, more 

 sparsely on the outer side. The tail is contained not quite two and a half times in the length 

 of the body, in one specimen little over twice ; it is well covered with short hairs. 



The feet are hardly large, although the claws themselves are more developed than in Tliomomys 

 bulbivorus. The longest claw projects beyond its digits (beneath) more than one-third the 

 length of the entire foot, and is decidedly longer than its digit. The first finger is well 

 developed, its claw reaching a little beyond the base of the central one. The second claw 

 reaches rather further than the fourth ; the end of the fifth to the base of the fourth. The 

 claws are all large, stout, and decidedly acuminate at the tip. The claws of the hind feet are 

 short, conical, and but little curved. The first toe is longer than the fifth, the second larger 

 than the fourth, the third longest ; the palms and soles naked, but the digits bordered by stiff 

 hairs on each side. 



The prevailing color everywhere above and below is a rich reddish brown or dark cinnamon ; 

 brightest on the sides and neck, duller and more mixed with ashy on the belly ; while along 

 the vertebral region is a uniform broad wash of dark brown, extending from the snout to the 

 root of the tail. There is little or none of the fine lining or mottling with dark brown or black 

 extending over the sides to the edges of the belly, as in T. bulbivorus, but this appears 

 concentrated in a uniform wash as described along the dorsal line, leaving the sides but little 

 different from the belly, except in being brighter. The bases of the feet and the basal two- 

 thirds of the tail all round are dusky, like the body ; the digits and extremity of the tail, with 

 the inside of the pouches are white. The chin, sides of the snout, and region bordering the 

 pouches are purplish brown, the region of the ears dusky. The claws are yellowish, except 

 where they show the extravasated blood through them. The fur is everywhere lead color at 

 the base. 



Measurements, (dry skins. ) 



