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, hut 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 hut 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 sldns .) 
No. 154. 
No. 149. 
Inches. 
Inches. 
Nose to occiput, about _ 
1. 60 
to eye, about _....._-_ 
.83 
to ear_ _ _ _ _ 
1. 33 
to root of tail_*_-_ 
6.33 
5.50 
Tail, from root to end of vertebrce -... 
2.50 
2.50 
from root to end of hairs.. 
2. 54 
2. 60 
uncovered portion.... 
?2. 08 
? 2. 00 
Ears, height internally above skull.. 
. 10 
. 11 
width 
. 16 
Arm, fore foot to end of claws, (cramped).-.. 
.86 
.80 
fore foot, longest claw ... 
.42 
.33 
longest claw and toe.. 
- .54 
.50 
Leg, hind foot from heel to end of claws.. 
1.00 
.94 
hind foot, longest claw.... 
.21 
. 17 
