850 



MONOORAPns OP NORTH AMEIIIOAN RODBNTIA. 



Il-l 



between Pembina and tlie Rocky Mountains, shows a considerable range of 

 color variation. It is, however, mainly individual, tiie variation occurring at 

 the sauio locality, covering nearly the whole range of variation presented by 

 the whole series. The differences consist mainly in the distinctness of the 

 mottling above and in the amount of fulvous pervading the general colora- 

 tion. In No. 1 1956, from Frenchman's River, the general color above is gray, 

 the light spots being almost white ; the sides, especially posteriorly, incline 

 to brownish; tlie lower surface is grayish-white, with a very slight but dis- 

 tinct tinge of fulvous. Another (No. 11963), from the same locality, is still 

 whiter below, with a rather browner cast above, wholly unvaried by spotting. 

 Still another (No. 1 1 954), also from the same locality as the others, is decidedly 

 reddish-brown, more varied with dusky above, while otherwise not different 

 from the last. Others differ from these in being strongly fulvous beneath, 

 with a more yellowish cast above. These can all be nearly matched by others 

 from tiie Milk River series, collected some two hundred miles further west. 

 The specimens most strongly suffused with tawny are from the Two Forks of 

 Milk River and the Three Buttes, these averaging more fulvous than speci- 

 mens from further eastward. Nos. 11975 (Three Buttes), 11953 (Two Forks 

 of Milk River), and 11945 (Milk River at 49°) present a strong contrast with 

 the pale phase already described, the lower surface being quite bright rusty- 

 yellow. Between tiiese extremes there is, however, almost every conceivable 

 intermediate stage. 



Var. TOWKSENDI. 

 . . , Townisend's Spermophile. 



Varietal chars. — Smaller than var. richardsoni, with larger ears and 

 much darker coloration. Length of head and body 6 75 to 8.50; of tail to 

 end of vcrtebnc 2.10 to 3.50; to end of hairs 3.35 to 4.60. Above, finely 

 varied with yellowish-gray and black, with generally a slight wash of dark 

 roddish-brown along tlie middle of the back and very indistinctly mottled ; 

 below, grayish-white, tinged more or less with brownish-yellow. Top of the 

 nase, ears, outer side of the fore and hind limbs, and buttocks reddish-brown, 

 often in striking contrast with the general coloration ; tail mostly black above, 

 edged with yellowish-white. The hairs individually, especially the lateral 

 ones, arc barred successively with black, the outer bar being very broad and 

 edged with yellowish-white. 



This variety is also represented by a large suite of specimens from a con- 



