450 RODENTIA 
continent. According to Mr. O. Thomas,! the latter “little animal 
is most nearly allied to the West-African 4. beccrofti, but differs 
from that species in its duller and less yellow upper side, in the 
entire absence of rufous on its neck and belly, and, as from all the 
other described species, in its diminutive size.” 
Family Scrcrw-£. 
Arboreal or terrestrial forms, with cylindrical hairy tails, with- 
out scales, and with 
twelve or thirteen 
pairs of ribs. Skull 
(Figs. 198, 199) with 
distinct postorbital 
processes; infra- 
orbital opening 
small; palate broad; 
P%; first upper pre- 
molar very small or 
deciduous; molars 
rooted, tubercular. 
Subfamily Seiur- 
ine.—TIncisors com- 
Fic. 198,—Lateral view of skull of American Marmot pressed form slen- 
(Arctomys monax). der ; tail long and. 
hairy. Cosmopolitan (excluding Australian region). 
This subfamily includes the true Squirrels, of which seven 
existing genera are usually recognised. 
Seturus.2—Tail long and bushy ; ears generally well developed, 
pointed, often tufted ; 
feet adapted for climb- 
ing, the anterior hav- 
ing four digits and 
a rudimentary pollex, 
and the posterior with 
five digits, all of which § 
have long, curved, and 
sharp claws. Mamme, 
from four to six. Skull 
(Fig. 199) lightly built, 
with long postorbital 
processes. Penultimate 
Fig. 199.—Palatal Aspect of cranium of Squirrel (Sefurus 
upper premolar, when bicolor). Natural size, 
present, minute. 
» Proce. Zool. Sov, 1882, p. 8. * Linn. Syst, Vat. 12th ed. vol. i. p. $08 (1766). 
