SCIURIDA—SPERMOPHILUS RICHARDSONI. 853 
Central Dakota, are quite similar, but are rather more strongly colored. 
These lead into the Camp Carling series and those from the North Platte 
(vicinity of the Medicine Bow Mountains), which are considerably darker, 
but among which are specimens almost undistinguishable from the more 
northern type. In the Camp Carling and Wind River Mountain specimens, 
the black annulations in the hairs of the upper surface begin to increase in 
extent, with a larger proportion of hairs wholly black, and a somewhat 
stronger wash of rufous over the middle of the back, while the fulvous tint 
of the sides becomes also more brownish. In the Fort Bridger specimens, 
the ear becomes still further enlarged; the black tips of the hairs are still 
longer and more conspicuous, in extreme examples (as Nos. 8372 and 3378) 
giving a strongly blackish cast to the whole dorsal surface; the lighter annu- 
lations become correspondingly narrower, and constitute merely a fine gray 
mottling. In other specimens, there is a nearly equal admixture of the dark 
and light shades, resulting in a uniform finely grizzled tint (as in No. 3320), 
with a faint wash of pale rufous, varying in some specimens to dull chestnut. 
In this phase (S. “armatus” Kennicott), the hairs of the dorsal surface are 
black at the base, then crossed by a broad bar of whitish, succeeded by 
another of pale rufous, extending nearly to the tips, which are shining black. 
The light subterminal bar varies from gray on the head, over the shoulders, 
and on tlie sides to pale rufous on the middle of the back. The nose and 
buttocks are usually strongly rufous. In var. richardsoni, there is a much 
broader subbasal zone of white, occupying generally two-thirds of the length 
of the hair; the dark rings are not so black, and the fulvous tipping is much 
paler. 
SYNONYMY AND NOMENCLATURE.—Spermophilus richardsoni was first. de- 
scribed and figured by Sabine, in 1822, from a specimen collected at Carlton 
House. Richardson gave a more detailed account of it in 1829. It was also 
described by Wagner, Audubon and Bachman, Baird, and others, who added, 
however, little to its history. Dr. Coues, in 1875, published: an excellent 
account of its habits, and contributed much to our knowledge of its distribu- 
tion. These descriptions, as well as various compiled accounts, relate almost 
wholly to the northern form, above characterized as var. richardsoni. Rich- 
ardson, however, as early as 1829, in the Fauna Boreali-Americana, described 
what is here recognized as var. fownsendi, he referring it doubtfully to the 
guttatus of Pallas and Temminck, which is an allied species of Siberia. 
