344 
U. S. P. R. R. EXP. AND SURVEYS-ZOOLOGY-GENERAL REPORT. 
than in A. monax. The body of the lower jaw is lower, the descending ramus projecting further 
backward than in A. monax. 
This animal agrees very well with the A. jlaviventer of Bachman, except in being chestnut 
colored beneath instead of yellow. This is, however, a difference of no consequence. 
A very imperfect skin, collected at Fort Dalles by Dr. Suckley, is in very imperfect fur, and 
does not furnish the materials for a satisfactory description. It is about the size of the northern 
hare, ( Lepus americanus,) and is just changing its fur, the new hairs being very short. The 
prevailing color above of the short hairs is a very pale grizzled brownish white and black, 
imparting a hoary appearance. The old soft under fur, however, is dusky at the base, then 
light brownish yellow, then brownish chestnut. The under parts are yellowish chestnut, the 
base of the fur darker ; the sides of the neck and shoulders, and the area round the fore legs, 
with the legs themselves, are similar, but more yellowish. The tail is yellowish rusty, becoming 
brownish towards the roots of the hairs. The end of the muzzle all round is whitish, margined 
all round by a broad band of rather dark brownish chestnut, interrupted under the throat. 
The soles of the feet are naked. 
This specimen bears a close resemblance to the Arctomys monax, but differs in the yellowish 
tail and legs. 
Although there are some differences in these two specimens, yet they are hardly of specific 
value ; at any rate, for the present I shall combine them and refer both to Arctomys jlaviventer, 
a species the essential character of which appears to be in having all the legs and feet reddish 
inside and out, in distinction to the universally black feet of A. monax. 
No locality is given by Bachman t£> his animal, having found it among some skins in the 
rooms of the Zoological Society of London. Supposed to have come from Western Texas or 
California. 
List of specimens. 
Catalogue number. 
Corresponding no. 
of skull. 
Age and sex. 
Locality. 
When 
collected. 
Whence obtained. 
Original number. 1 
Nature of spe¬ 
cimen. 
Measurements. 
i 
0 
1 
| Tail to end of 
Tail to end of 
hairs. 
Hind ft.,length 
Skull, length. 
Skull, width. 
Width of muz¬ 
zle. 
'997' 
1525 2 
Q 
Fort Dalles, O. T .... 
Black Hills, Neb. 
May 20, 1855 
1855 
Dr. Geo. Suckley. 
60 
Skin. 
14.75 
22.00 
4.50 
8.00 
6.50 
10.00 
2.80 
1372 
Dr. F. V. Hayden. 
...do . 
3.62 
2.46 
.94 
> Measured before skinning. 2 Much stretched. 
