[51.] 7. A rctomys (S permophilus) guttatus? The American Souslik.
Mus citillus, var. guttata. P allas, GUr. tufa 6; B. ?
Spermophilus guttatus. T emminck, Tab. Jffeth. ?
A; Spebmophiltjs (,guttatus Atnericanus) auriculis nullis, corpore super xerampelino crebemme, albo guttalo subter-
ochreo, cauda abbreviaia corpore concolori, naso convexo ferrugineo, palpebris labiisque albidis.
American Souslik, without external ears, having the upper parts of a clove-brown colour, varied by small crowded white
spots, the under parts and feet ochre-coloured, a short tail coloured like the body, convex reddish-brown
nose, and whitish eyelids and lips.
Mr. Douglas brought a small marmot from the western side of the Rocky
Mountains, and several injured specimens of the same species exist in the Museum
of the Hudson’s Bay Company. I can detect no external characters (except that
the spots on its fur are more “crowded and indistinct) to distinguish it from the mus
noricus of Agricola or Hungarian Souslik, which I know only from the descriptions
and figures' given by authors ; but a scull of the latter preserved in the College of
Surgeons, although of the same size with the American animal, differs from it in
having a more arched facial line, and in possessing ail uniform degree of curvature
from the occiput to the end of the nose. The American Souslik has a convex
nose, with the frontal bone depressed between the orbits as in the A. Richardsonii.
It resembles the A. Parryi very closely in the colours and markings of its fur,
though it has not, when recent, one-third of the weight of that animal, and its feet
and claws are much smaller, being less than those even of the A. lateralis. I
have been able to collect no particular information respecting its habits. It
seems to be confined to the western declivity of the Rocky Mountains. Buffon
mentions that the name of Souslik given to the A. guttatus, on the Wolga, is
intended to express the great avidity that animal has for. salt, which induces it to
go on board vessels laden with that commodity, where it is often taken.
D E S C R I P T IO N .
Dentition precisely similar to that of A. Richardsonii. Incisors slightly yellow. Cheek-
pouches. Nose obtuse; facial line slightly arched. Whiskers black, not strong. No external
ears, the auditory opening being surrounded merely by a thickish margin, having the appearance
of the cicatrix of an ear that has been cut off. Colour.—The upper surface of the nose is
reddish-brown, mixed with a few black and some white hairs. The upper lip, the upper and
under eye-lids, and the whole under jaw, are white. The cheeks and upper aspect of the
head are of a mixed gray colour, produced by the fur being dark brown, ringed towards the
tips with white and frequently tipped with black. The whole of the back and upper surface
of the tail has a motled gray colour, produced by numerous small, somewhat quadrangular
white spots, spread over, a dark, ground, of a colour intermediate between clove and liver-
browns. Thé white nearly equals, the brown in quantity, and the spots are less distinct
towards the sides. The fu r is short and not very fine, dark towards the roots, ringed with
white above, and intermixed with longer hairs, having black tips. The throat, breast, belly,
under surface of the tail, and the extremities, are of a pale ferruginous colour, approaching to
ochre-yellow.
The tail is rather slender, and, excluding the fur at its tip, is about the same length
with the posterior extremities when stretched- out, or about one-seventh of the length of
the body. The extremities are shaped like those of the other spermophiles, but the toes and
claws are more slender than usual. The palms are naked,' and are entirely occupied by five
tubercles, viz. three at the roots of the toes, and two behind them of a larger size. At the
base of the inner posterior tubercle there is a small convex obtuse nail, which is the only
vestige of a. thumb. As is usual in the spermophiles, the second fore-toe and daw is longer
than the others, the third is scarcely longer than the first, and the fourth is the length of its
claw shorter than the third. The fore-daws are, slender, much compressed, and slightly,
curved. The soles are naked, but in some measure protected by the hairs which curve in
from the margins of the tarsus. The three middle toes are nearly equal in length, the fifth is
considerably shorter, and the first is shorter than the fifth. The hind claws are much shorter,
not so. much compressed, less curved, and more excavated beneath than the fore ones. All
the* claws are black.
Length, of the head and body . * 8
M body * • 6
head ' • * 2
,, tail (vertebra) « 1
,, tail, including fur . 2
. from wrist joint to end of middle
fore-daw . »- * *
middle fore-daw * 0
Dimensions.
Lines. , . 6 Length from heel to end of middle hmd-daw 1
6 n of the middleihind-tee and daw . 0
0 middle hind-claw . 0
g M cranium from end of the
3 nasal bones to the occipital spine . 1
,r nasal bones- , . 0
0 Breadth of the frontal bones between the
3J I orbits . . • • 0
3
6
'ïè'
6è
3|
Length of the head and body
:>J( tail
tail, including the fur
Dimensions
Of a second specimen.
In ch e s. Lines. Lin e s.
, 9 6 . 1 Length from the anterior part of the orbit to
l 6 I the end of the nose . * « 7 $
. 2 0 I