828 



HONOOKArnB OF NOKTU AMBBIOAN UODEMTIA. 



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white, becoming browni8h-white on the inaide of the limbs; hairs all dark 

 basnlly. Eyelids white, forming n 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 

 widtii — 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. 



Habitat. — Colorado and Western Texas, southward into Mexico, and 

 westward to the Sierra Nevada Mountains. 



General form much as in the true Squirrels (Sciurus). Ears high and 

 broad, as large as in most species of Sciurui. 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 Spermophilc, 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 bo 

 flattened, with the outer surface grooved. 



Diiferent 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 longitudir<il bands seen in ywn. beecheyi 

 and douglam. In several specimens from Soda Springs, Colo, (as in Nos. 

 9565, 9562, and 956J), and in others from Ogden and Provo, Utah (as in 

 Nos. 11133, 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 

 8|)ecimens, the white so predominates over the black as to form a white 

 ground-cok)r 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 

 H|)ccimeH8 collected by Mr. Uenshaw in Arizona, the surface of the i>elage 



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