310 IMOMHM.WIilS OF NOKTII AMERICAN EODENTIA. 



marked contrasl with the mixed white and brown winter pelage of specimens 

 from the Eastern States: and even the specimens from the highest northern 

 localities, though pure white at the surface, are fulvous and then plumbeous 

 beneath. These specimens agree, however, in this character with winter 

 specimens from Fort Bridger, Fort Benton, and the Bitter Root Valley, 

 which, from the locality, I have referred to var. bairdi, and are in no way 

 distinguishable from them. I have also Included specimens from "Koko- 

 youkuk, R. Am.'', in changing pelage, in this series, which they seem to 

 approach quite strongly. 



The skins of var. washingtoni vary in length of body from 15.25 to 

 18.50 inches, eight specimens giving an average of 16.63, or about one inch less 

 than the average of var. virginianus, and half an inch more than specimens 

 from the northern districts of the fur countries, or var. americanus. The ear 

 fully equals, and the hind foot scarcely falls short, of the length of the same 

 parts in var. virginianus from Massachusetts. The single fully adult skull 

 fully equals the average of eastern examples. The measurements given in 

 'fable XIX are taken wholly from the skins, many of which are unfilled and 

 evidently much shrunken. The measurements of the skulls (Table XX), as 

 before stated, are mainly from more or less immature specimens. The pro- 

 portions are not essentially different from those of eastern specimens of cor- 

 responding age, and the ears and tarsi are fully equal to these parts in var. 

 virginianus, instead of being shorter, as has been supposed. 



Var. bairdi. 

 Rocky Mountain Varying Hare. 



Size and proportions same as those of the other varieties of americanus. 

 Winter pelage sometimes wholly snowy-white to the base, as in the Arctic 

 Hare; generally with the outer white zone extending much deeper than in 

 any other form of americanus, with the middle zone much paler, varying from 

 a faint shade of fulvous to a delicate salmon tint, and the basal plumbeous 

 zone greatly reduced in extent, and lighter-colored. In summer, above pale 

 grayish-brown and black, the black being often the prevailing tint; under-fur 

 whitish, sometimes almost pure white, with the middle brown zone of the 

 other forms obsolete; under parts (excepting the pectoral region) and the feet 

 pure white; general color of the ears black, washed more or less with whit- 

 ish, and with a very broad conspicuous white border. 



In different specimens, the color of the dorsal aspect in summer varies 



