101 
The Squirrels as a group are arboreal; they nest in trees, eat the fruits 
and buds of trees, and rarely go to the ground except for food. They 
have a light and graceful but muscular form; their nails are strong and 
sharp; they climb and leap with the greatest ease, aided by their large 
and bushy tails, which support and steer them while in the air. The 
fore feet are prehensile, the Squirrel seizing and holding its food with 
its hands, standing on the hind feet while eating. Except the Flying 
Squirrels, they are diurnal, keeping in the trees at night, and usually 
for a few hours in the middle of the day. The fur is nearly valueless; 
the flesh properly cooked is excellent food. As a group they are timid, 
readily domesticated, active in confinement, becoming agreeable and in- | 
telligent pets. Their main food is nuts, although they take insects at 
times, and are often so fond of the cereal grains as to be a nuisance to 
farmers. Indeed in 1749 Pennsylvania paid $40,000 from the public 
treasury in premiums for the destruction of Squirrels. From the nature 
of their retreats, and natural activity, they evade the attacks of rapacious 
animals. Preying birds, reptiles, Wild Cats, and Martens at times cap- 
ture the young, and rarely the old. Man is their worst enemy, although 
some species are most abundant in the pioneer settlements. 
KEY TO THE GEN“ A OF SCIURIDA. 
* A densely furred membrane aiong the sides between anterior and p:«sterior limbs; | 
tail depressed, flattened, densely iurred; permangnt molars 5-5 above. 
SCIUROPTERU 
* * Sides without membrane specially modified. 
+ No cheek pouches; tail bushy, at least as long as body; ears long; no black 
stripes along the back. : f : mwas: 2einy®, woae Pe SCLURUS! 
+ t Cheek peuches present. 
+ Back with three to five distinct black stripes; tail shorter than body, not 
bushy; cheek pouches well developed. 5 6 5 : TAMIAS. 
+ 1 Not as above; body rather slender, squirrel like; cheek pouches well de- 
veloped; claw of thumb rudimentary or wanting. SPERMOPHILUS. 
t tt Body large, thick-set, depressed ;, cheek pouches shallow; thumb rudimen- 
tary, armed with a small flat nail, not a claw; soles naked. 
ARCTOMYS. 
GENUS SCIUROPTERUS. F. Cuvier. 
Ktymology: Greek, Skiouros, a Squirrel; Pteron, a wing. 
Scvurus, Linn., (in part) and of early authors generally. 
Pteromys, G. Cuvier (in part), and most recent authors. 3 
Sciuropterus, ¥. Cuvier, Ann. du Mus., x, 1825, 126, pl. x. (Type, Sci- 
urus volans, Linn.) 
Generic Characters—Skull short, broad, highly arched, in general form, 
a miniature of Sciwrus hudsonius, but the supra-orbital notch deeper, 
