MAMMALS OF MINNESOTA. 155 
Genus SCIURUS, Linn. 
Aside from obvious differences in habits, the true squirrels 
may be distinguished from the chipmunks and gophers by the 
broad head and curved dorsal outline of the skull. Skullshort, 
broad, cranial portion expanded, facial portion rather broad ; 
malar bone nearly vertically expanded; post-orbital process 
produced and slender ; first premolar, if present, very small. 
Pelage full, tail full and bushy, back never striped, no cheek 
pouches. It is unnecessary to speak of the characteristics of 
so familiar an anima]. Every one whose boyhood brought him 
within the influence of Nature at all must remember more than 
one escapade in which this furry tree-farer played an important 
part. 
Some fourteen species occur in America, some of which are 
very closely allied. Our own state has but three species. 
Central America seems to be the focus of the genus on this 
continent, and here the species are not only the most numerous 
and variable but the largest as well. Toward the north and 
south the size diminishes, and a tendency is observed to depart 
from the typical characters of the genus. The tail especially is 
reduced. 
The following table copied from Allen’s monograph will be 
found useful: 
SYNOPSIS OF NORTH AMERICAN SCIURI. 
I. Tail very short and narrow, the caudal vertebre alone 
about two-thirds as long as head and body; tail to end of hairs 
about one-seventh shorter than the head and body; premolars 
+, the first very small and often deciduous; a narrow, black, 
lateral line; size small. 
1. Above greyish, mixed with yellowish or reddish, annu- 
lated with dusky, often with a strong wash of ferruginous 
along the middle of the back; below generally white, some- 
times narrowly annulated with black; in one sub-species fulvous 
below. Hab. Northern half of North America. 8S. hudsonius. 
(a). Above varied with black and yellowish-rusty; upper . 
surface of tail with hairs gray at the base and tips, with a 
broad subterminal bar of black. Hab. Central portion of Rocky 
Mountains and thence westward to Sierra Nevadas. 
var. fremonti. 
(b). Above dusky, strongly varied with reddish; upper 
surface of tail with the hairs dark reddish brown at the base, 
