828 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
white, becoming brownish-white on the inside of the limbs; hairs all dark 
basally. Eyelids white, forming a conspicuous light eye-ring. Ears inter- 
nally and posteriorly brownish-yellow; anteriorly dark brown, varying to 
black. Tail white and black in alternating longitudinal bands of nearly equal 
width—two black and three white. The hairs individually are white at the 
tips, with two broad bands of black separated by white; the extreme base is 
often also black, but usually white. Occasionally presents melanistic phases 
of coloration. 
Hasirat.—Colorado and Western Texas, southward into Mexico, and 
westward to the Sierra Nevada Mountains. 
General form much as in the true Squirrels (Sciwrus). Ears high and 
broad, as large as in most species of Scturus. Tail full and bushy, distich- 
ous; the hairs two to two and a half inches long, giving a breadth to the tail, 
when the hairs are outstretched, of four to five inches. Palms and soles 
(generally) wholly naked. Claws rather short for a Spermophile, yet decid- 
edly fossorial rather than Sciurine. Pelage coarse but not rigid; under fur 
sparse, especially in summer. The hairs, when magnified, are seen to be 
flattened, with the outer surface grooved. 
Different individuals vary greatly in coloration, the color of the upper 
surface ranging from nearly pure gray (especially anteriorly) to strong reddish- 
brown, while that of the lower surface varies from pale yellowish-white to 
reddish-brown. The gray is generally purest over the shoulders, but is fre- 
quently developed on the sides of the neck and shoulders, with the inter- 
vening dorsal space either darker or more suffused with rufous. There is 
thus an approach to the distinct gray longitudinal bands seen in vars. beecheyt 
and douglassi. In several specimens from Soda Springs, Colo. (as in Nos. 
9565, 9562, and 956), and in others from Ogden and Provo, Utah (as in 
Nos. 11138, 11135, and 11147), the gray forms a continuous mantle, cover- 
ing the whole anterior half of the dorsal surface, sharply bounded behind 
by the reddish-brown of the posterior half of the back. In others, the gray 
blends gradually into the brownish. In some of the Soda Springs and Ogden 
specimens, the white so predominates over the black as to form a white 
ground-color minutely grizzled with black. In some, the gray mantle is more 
or less distinctly divided by a mesial space of brownish, thus showing a com- 
plete resemblance to var. beecheyi. Occasionally, as especially in several 
specimens collected by Mr. Henshaw in Arizona, the surface of the pelage 
