MAMMALIA. 471 



furnished with hair ; a large head, with erect ears ; projecting and brilliant 

 eyes ; the upper lip divided. There are four toes before, with a tubercle 

 covered by a blunt nail, and five behind ; four molars on each side, above 

 and below, variously tuberculated ; a very small additional molar is seen in 

 front and above, permanent in some species, but drops out in most cases 

 when the young have attained the age of six to twelve weeks ; the fingers 

 are long, slender, and deeply cleft ; the nails very acute, and greatly com- 

 pressed. We quote tlie following description of the habits of the squirrels 

 from Audubon and Bachman, Quadrupeds, p. 38 : 



" Squirrels are able to leap from branch to branch, and from tree to tree, 

 clinging to the smallest twig, and seldom missing their hold. When this 

 happens to be the case, these animals have an instinctive habit of grasping, 

 in the descent, at the first object which may present itself; or, if about to 

 fall to the earth, they spread themselves out in the manner of the flying 

 squirrels, and thus, by presenting a greater resistance to the air, are enabled 

 to reach the ground without injury, and, recovering instantaneously, they 

 ascend the nearest tree. 



" All the American species of this genus, as far as we have been able to 

 become acquainted with their habits, build their nests either in the fork of 

 a tree, or on some secure portion of its branches. The nest is hemispherical 

 in shape, and is composed of sticks, leaves, the bark of trees, and various 

 kinds of mosses and lichens. In the vicinity of these nests, however, they 

 have a still more secure retreat in some hollow tree, to which they retire in 

 cold or in very wet weather, and where their first litter of young is generally 

 produced. 



'* Several species of squirrels collect and hide away food during the abun- 

 dant season of autumn, to serve as a winter store. This hoard is composed 

 of various kinds of walnuts and hickory nuts, chestnuts, chinquepins, acorns, 

 corn, &c., which may be found in their vicinity. The species, however, 

 that inhabit the southern portion of the United States, where the ground is 

 seldom covered with snow, and where they can always derive a precarious 

 support from the seeds, insects, and worms, which they scratch up among 

 the leaves, &c., are less provident in this respect ; and of all these species, 

 the chickaree, or Hudson Bay squirrel {S. hudsonins\ is by far the most 

 industrious, and lays up the greatest quantity o\' food. 



" In the spring, the squirrels shed their hair, which is replaced by a thin- 

 ner and less furry coat; during summer, their tails are narrower and less 

 feathery than in autumn, when they either receive an entirely new coat, or 

 a very great accession of fur ; at this season, also, the outer surfaces of the 

 ears are more thickly and prominently clothed with fur than in the spring 

 and summer. 



" Squirrels are notorious depredators of Indian corn fields of the farmers, 

 in some portions of the country consuming great quantities of this grain, 

 and, by tearing off the husks, exposing an immense number of the unripe 

 ears to the mouldering influence of the dew and rain." 



Twenty species of this genus inhabit North America. The common or 

 red squirrel (*S'. hudsonius) has a great geographical range, and extends 



676 



