268 NORTH AMERICAN MUSTELIDiE. 



pale endiug of the hairs seems constant, even when there is 

 most tawny in the body of the furs. Owing to the length and 

 coarseness of the pelage, the animal usnally presents, when 

 prepared for the museum, a patchy or streaky appearance, the 

 completely blended grizzle being interrupted by the slightest 

 disturbance of the set of the hairs. Beneath, the animal is 

 uniformly as above, minus the black or blackish. The feet are 

 dark brown or blackish ; the claws are generally light-colored, 

 especially those of the fore feet. 



In examining a large suite of specimens from various locali- 

 ties in the United States west of the Mississipi^i, I find decided 

 expression of a variation dependent upon climatic influences. 

 Specimens from the comparatively fertile and well-watered 

 regions upon the eastern border of the great central plateau 

 are identical in tone with others from the Pacific slopes, and 

 both much more heavily colored than those from the arid 

 intermediate region. In the former, the fulvous or tawny tinge 

 X)redominates among the lighter colors, mixed with a large 

 amount of nearly pure black. As remarked by Prof. Baird, 

 the resemblance of these specimens to the Woodchuck {Arc- 

 tomys monax) is striking. In all the specimens from the inte- 

 rior dry region, and especially from the Upper Missouri, where 

 the animal is extremely common, there is little if any of the 

 fulvous. At a distance, the animal appears nearly white ; the 

 general color is white', soiled with a faint tawny or dirty yel- 

 lowish-tinged and mixed with but little blackish, the dark 

 part of the individual hairs being less extensive than even the 

 terminal hoary portion, and the area where the black occurs at 

 all being restricted. In these cases, also, the general grizzle 

 encroaches most on the head, and the frontal white stripe 

 reaches farthest along the nape. Under these conditions, the 

 animal very closely resembles in coloration the brindled gray 

 Wolves of the same geographical area. 



It is almost needless to add that the gradation between the 

 extremes above noted is unbroken and insensible. 



^one of the specimens now under consideration show the 

 slightest trace of a vertebral white stripe beyond the nape. 

 Those exhibiting this peculiarity are treated under the next 

 head. 



Without alcoholic specimens, or measurements taken in the 

 flesh, I cannot give the dimensions with desirable x>recision, as 

 all the dried skins before me are more or less distorted. The 



