408 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
the back and rump. Anteriorly the black-tipped hairs are fewer, and the 
dorsal aspect, from the shoulders anteriorly to the nose, is generally more or 
less strongly tinged with pale yellowish-brown, in strong contrast with the 
remainder of the dorsal surface. The sides of the body are generally still 
more strongly washed with yellowish-brown, which, over the ventral surface, 
assumes a much paler tint. In young specimens, the black-tipped hairs are 
much fewer, and the pelage generally grayer. The ears, which are well 
haired on both surfaces, are grayish, tinged more or less with pale yellowish- 
brown, except anteriorly on the outer surface, where is a large dusky area. 
They have a well-marked whitish or yellowish-white margin. Anterior sur- 
face of all the feet yellowish-brown, nearly as bright as on the sides of the 
body. Soles of the hind feet dusky; palms pale yellowish-brown. Large 
naked black pads at- the base of all the toes. Whiskers numerous, one to 
two and a half inches long; in some specimens nearly all black, in others 
only the upper are black, the lower being light-colored to the bases: gener- 
ally a part have the basal portion black, with the apical half or two-thirds 
yellowish white. 
A series of over thirty skins now before me, all taken at one locality and 
on the same day, show a great range of individual variation in color through 
the varying intensity of the fulvous suffusion. In some specimens, it is a very 
pale wash of yellowish-brown, while in others it is strongly yellowish, which, 
iu still others, becomes decidedly rufous, especially on the sides of the neck 
and shoulders and on the top of the head. In one specimen (No. 2841, M. 
C. Z. Coll.), the whole upper surface of the head is bright chestnut, and the 
usual pale fulvous suffusion on other parts of the body is decidedly rufous, 
rather than fulvous, No. 2763 (M. C. Z. Coll.) is strongly tinged throughout 
with yellowish-brown. On the other hand, No. 2682 (M. C. Z. Coll.) has 
only a faint yellowish-brown tinge, which is scarcely perceptible on the ven- 
tral surface. These specimens are, however, all adult males. There is 
apparently no sexual difference in color; some of the palest specimens; as well 
as the brightest, being males. Young specimens differ from the adult in 
being generally more grayish, with fewer black-tipped hairs in the dorsal 
surface. The fulvous suffusiun is generally paler, but in some specimens is 
as bright as in average adults. 
The texture of the pelage is much as in the Arvicola, especially the 
large A. xanthognathus, being much firmer than in the Hares, with a much 
smaller amount of soft under-fur. 
