SCIURID^-SPBBMOPBILUS EMPETRA AND VARIETIES. 841 



Var. krythkogluTjEus. ■ < 



Varietal chars. — Somewhat Rmaller than var. empetra, with longer ears 

 and tail. Length of head and body about 9.r)0 (to 11.00, according to Rich- 

 ardson); of tail to end of vertebrae 3..50; to end of hairs 5.00. Color simi- 

 lar, but darker, with the lighter markings generally more fulvous. 



Two skulls of var. erythroglutam give an average length of 2.06 against 

 2.25 in six skulls of var. empetra; average widtli 1.27 against 1.48 in var. 

 empetra. The skull is hence relatively narrower and more elongate than in 

 the latter, and the postorbital processes are more slender. Part of this dif- 

 ference may, however, be the result of differences of age, the erythroglutceus 

 skulls being from younger animals than the others. 



This variety was first described by Dr. Richardson, from specimens pro- 

 cured west of the Rocky Mountains, " near the sources of the Elk River, in 

 latitude 57°". Two of the five specimens before me are from the Kootenay 

 River, two from the head of Flat Head River, and the other from the upper 

 end of Plover Bay. These agree with Dr. Richardson's description, except 

 that they are rather smaller. They are also from considerably more southern 

 localities. In one specimen, the light blotches are as distinct and as light as 

 in var. empetra. 



aENKRAL REHA&KS RGSPECTmG SFERHOPHILUB PARRTI AND ITS VARIETIES. 



Differential characters and affinities. — Spermophilus empetra, in all 

 its forms, is widely different from any other North American Spermophile, 

 with none of which it is necessary to compare it in detail. It more nearly 

 approaches 8. gramtnurus than any other, especially in cranial characters. 

 It has larger ears than any other of the species of the subgenus Colobotis, 

 and in general features stands between Otospermophilus and Colobotis, but 

 agrees best with the latter. 



It finds in the Siberian S. eversmanni a very near ally, but 8. empetra 

 differs from 8. eversmanni in being larger, with a much shorter tail and more 

 rufous on the head. Var. kodiacensis, from the island Kodiac, situated off 

 the southern coast of the Aliankan Peninsula, in color very closely resembles 

 the 8. eversmanni, but it has a shorter tail than even var. empetra. Examples 

 from Arikamtchitchi Island and the western shore of Behring's Strait are 

 still more like 8. eversmanni, yet are not varietally separable from var. empetra. 



Synonymy and nomenclature. — This species was first notieed in 1772 



