SCIURIDA—SPERMOPHILUS EMPETRA AND VARIETIES. 841 
Var. ERYTHROGLUTAUS. 
VARIPTAL CHARS.—Somewhat smaller than var. empetra, with longer ears 
and tail. Length of head and body about 9.50 (to 11.00, according to Rieh- 
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. erythrogluteus give an average length of 2.05 against 
2.25 in six skulls of var. empetra; average width 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 erythrogluteus 
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. 
GENERAL REMARKS RESPECTING SPERMOPHILUS PARRYI 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 S. grammurus 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 S. empetra 
differs from S. 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 Aliaskan Peninsula, in color very closely resembles 
the S. 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 S. eversmanni, yet are not varietally separable from var. empetra. 
SYNONYMY AND NOMENCLATURE.—This species was first notieed in 1772 
