394 U. Ss. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
THOMOMYS DOUGLASSII. 
Copher. 
Geomys douglassii, Ricu. F. Bor. Am. I, 1829, 200 ; pl. xviii, C, fig. 1-6. (Skull.)—Is. Zool. of Blossom, 1839, 12°, 
Leconte, Pr. A. N. Sc. Phil. VI, 1852, 162. 
Ascomys douglassii, WAGNER, Suppl. Schreb. II, 1843, 392. 
Pseudostoma douglassii, Aup. & Bacu. N. Am. Quad. IIT, 1853, 24 ; pl. cv. 
Thomomys douglassii, GreBEL, Saugt. 1855, 531. 
Geomys fuliginosus, Scu1nz, Synop. Mamm. II, 1845, 36. 
Sr. Cu. —Cheek pouches large ; sparsely haired on the outer wall. ‘Tail, one third to nearly one half the body. Upper 
incisors nearly plane in front, with a distinct and sharp groove. Hand large ; claws very large and stout ; palm and digits 
very short. Middle claw 5} lines above ; below, occupying nearly two-fifths of the hand ; its toe about two-eighths. First 
finger or thumb very short, barely reaching over two-sixths the hand. 
Color.—Above, dusky chestnut brown, but slightly mottled on sides and beneath with an ashy brown tinge. Cheek 
pouches whitish at the bottom, the line of demarcation indistinct, and the brownish color of the marginal region running 
down into the pouch. Tail grayish ; dusky above. 
This species has the depressed form of body, without indication of neck, &c., of the genus. 
The ears are quite large, being distinctly evident as a margin to the auditory aperture. The 
whiskers are short and white ; the cheek pouches ample; scantily furred within, especially on 
the side opposite to the jaws. The incisors are yellow, plane in front, or only rounded at the 
edges ; the inner edge of the upper ones with a distinctly marked and sharp though delicate 
groove, differing decidedly in the flatter incisors and distinctness of groove from 7. bulbi- 
vorus. The tail is moderate, contained nearly three times in the length of the body; it is 
depressed and somewhat flattened at the tip, and well covered with short stiff hairs. The fur 
is fine, soft, and silky. The feet are large and strong ; the fore feet with the claws much curved, 
compressed, trenchant, and long. The thumb is unusually short, almost rudimentary ; the tip 
of its claw not extending to the fissure between the second and third, and barely to the end of 
the bulb of the fifth. The third claw is, as usual, the longest, and of great development ; it 
occupies nearly two-fifths of the total length of the hand from the posterior part of the tubercle. 
The palm and fingers are, however, unusually short, the third claw extending beyond the bulb 
one-fourth longer than the length of this finger, which indeed is contained nearly four times in 
the total length of the hand. The second and fourth claws are about equal ; the tip of the fifth 
does not reach quite to the end of the bulb of the fourth finger. On the hind foot the third 
claw extends furthest ; the second is a little longer than the fourth, and the first than the fifth. 
The upper parts are of a reddish or chestnut brown, not appreciably darker on the back ; 
brightest and clearest along the occiput. On the sides and beneath, the lead colored bases of 
the hairs are exhibited to a considerable extent, the ends tipped with pale grayish or ashy 
reddish brown; anteriorly, on the throat, between the fore legs and region around the cheek 
pouches, the prevailing tint is a purer grayish ash. The edge of the lips and the top of the snout 
are dusky, but the pouches are whitish on the inside near the bottom and do not exhibit the 
sharp and decided contrast of white and dark brown seen in 7, bulbivorus. The region behind 
the ear is dusky. The feet are dull grayish white; the tail is similar, with a dusky line along 
a part of the upper surface. 
The fur exhibits little mottling with dusky; the sides being nearly plain, thus differing 
considerably from 7’. bulbivorus. The sides are more ashy and the under parts with less red. 
