SPERMOPHILUS. 135 
of large internal cheek-pouches, as well as by the first digit of the fore foot being rudi- 
mentary or absent, and by cranial and dental characters. The genus is one highly 
characteristic of the Palearctic and Nearctic Regions, but four species are found within 
our limits. These may be characterized as follows :— | | 
1. S. annulatus. Length about 9°50, of tail-vertebree 6"50. Ears large. Upper 
parts varied with tawny and black, shoulders and fore limbs bright rufous ; 
lower parts fulvous. ‘Tail long, narrow, its upper surface with broad trans- 
verse black stripes. 
2. S.grammurus. Average length 12"; tail-vertebre 8”. Ears large. Upper parts 
mottled tawny and black; lower parts pale fulvous. Tail bushy, more than 
two-thirds the length of the head and body, its lower surface with three black 
lateral lines. 
3. S. spilosomus. Average length 7", of tail-vertebre 3”. Ears almost obsolete. 
Upper parts reddish brown, with subquadrate whitish spots, which are not 
arranged in rows; lower parts yellowish white. ‘Tail narrow, half as long as 
the head and body, its lower surface with one lateral black band. 
4, S. mexicanus. Average length 8", of tail-vertebre 4”, Ears small but distinct. 
Upper parts reddish brown, with subquadrate white spots arranged in longitu- 
dinal rows ; lower parts whitish. Tail fuller than in last species. 
1. Spermophilus annulatus. 
? Sciurus lewisi, Hamilton-Smith, Griffith’s Cuvier’s An. Kingd. iii. p. 190, pl. (1827)*. 
Spermophilus annulatus, Audubon & Bachman, J. Ac. Philad. viii. p. 8319 (1842, descr. orig.)’; 
Quad. N. Am. ii. p. 218, pl. Ixxix.*; Allen, Mon. N.-Am. Rodent. p. 886%. 
Hab. Mexico, plains of Colima (Xantus, U.S. Nat. Mus.*). 
As Mr. Allen has pointed out, this is probably the Sciurus lewisi of Hamilton-Smith!; 
but I agree with him in considering its identity to be too doubtful to allow of the name 
being used. The first trustworthy description of the species is that of Audubon and 
Bachman 2, founded on a specimen of uncertain origin, but believed to be “ from the 
western prairies.” No further examples were known for many years; and Professor 
Baird suggested that the type (which appears to have been lost) might have been an 
example of a West-African Squirrel, Sciwrus rufo-branchiatus, Waterhouse *—an identi- 
fication which was afterwards positively made by the late Mr. Andrew Murray. But 
Mr. Allen has described a specimen in the National Museum at Washington, obtained 
by Xantus near Colima in South-western Mexico, which proves that the animal is a 
true Spermophile, though very Sciurine in general appearance. The skull is unfortu- 
* Mamm. N. Am. p. 327. + Geogr. Distr. Mamm. p. 359. 
