Page:The American Cyclopædia (1879) Volume XV.djvu/309

 SQUIRREL 297 followed by many English and French surgeons. The operation has now become very common, though the best surgeons admit that there are three classes of cases in which it should not be performed, viz. : those in which the position of the eye is fixed, those which result from the paralysis of the antagonist muscle, and those occurring in infants before dentition. The operation is not difficult nor particularly dangerous, and is generally suc- cessful. There are two methods of perform- ing it, the ordinary or that of Dieffenbach, where the conjunctiva is divided and the mus- cle to be severed is laid bare, and the subcon- junctival, where the conjunctiva is divided to a much less extent. The latter is generally preferred. SQUIRREL, the popular name of the rodents of the family sciuridce, which is very numerous in species, and widely spread over the world, except in Australia. They are characterized by a broad head, the frontal bone being dilated into a post-orbital process ; the muzzle wide, from the development of the frontal and na- sal bones ; eyes large and prominent, ears moderate, and whiskers long; the hind feet five-toed, the fore feet four-toed, with a wart- like thumb, all the fingers and toes with com- pressed and curved claws ; the fur is gener- ally soft, especially in the northern species, and the tail is long, hairy, expanded laterally in the arboreal genera, and shorter and bushy in the terrestrial, and in both carried grace- fully over the back ; the upper lip is cleft, the Cfflcum large, clavicles perfect, enabling them to use the fore limbs to convey food to the mouth, and the tibia and fibula distinct ; some have a membrane extended between the fore and hind limbs. (See FLYING SQUIEEEL.) The incisors are f, smooth in front, brown or orange, the lower compressed and sharp ; mo- lars fif, rooted, tuberculate, with projecting transverse stria enamelled continuously, the anterior upper one the smallest and sometimes deciduous. The food is chiefly vegetable, though some American species are known to suck eggs and destroy young birds. The family is very abundant in North America, nearly one third of all the species being found here ; the prairie dogs and prairie squirrels are peculiar to this continent, as well as most of the fly- ing squirrels. (See PEAIEIE DOG, and PEAIEIE SQTJIEEEL.) The genus sciurus (Linn.) is the type of those of the family which live in trees ; the species of the United States are hard to determine from the tendency to variation in color (red, gray, and black being the predomi- nating tints), and the diminution in size in the southern states. Baird gives it as a general rule that, when a squirrel has the fur of the throat or belly annulated, it is a variety of some species which normally has the under parts uniformly white or reddish to the roots, or the latter plumbeous. The bones of the red-bellied squirrels are generally red, and of the white- bellied white. The largest of the North Amer- ican species is the fox squirrel of the southern states (8. vulpinus, Grnel.), about 2J- ft. long, of which the tail is 15 in. ; the head is rather slender and pointed, and the tail rather cylin- drical ; the upper molars are permanently four. The color varies from a gray above and white below, through various shades of rusty, to uni- form shining black ; the fur is coarse and harsh, and the ears short ; the ears and nose are white in all its varieties. It is found from North Carolina through the S. Atlantic and gulf states to Brazos river in Texas. The gray vari- ety is the 8. capistratus (Bosc), and the black the S. niger (Linn.) and the black squirrel of Catesby. It prefers elevated and open pine ridges where there are occasional oak, hickory, and other nut trees ; the nest for the winter and breeding seasons is made in a hollow tree, and in summer in the forks between the branches. The young are born in March and April, and fed by the parents for four or five weeks. The food consists of acorns, nuts, fruit of the pine cones, green corn in summer, buds and roots in spring, and whatever it can get in winter, as it does not appear to lay up any winter stores, or to resort to any hoards previously buried. When alarmed, it makes for a hollow tree ; it is a swift runner, defends itself boldly, and is very tenacious of life ; it is generally seen toward the middle of the day ; it is easily do- mesticated, but is less active in the cage than the smaller species ; its flesh is frequently eat- en. The cat squirrel (S. cinereus, Linn.), the fox squirrel of the middle states, is 25 or 26 in. long, of which the tail is about 14 in. ; the head is very broad, the muzzle short and cat- like, the body thick and heavy, and the tail large and flattened ; the color varies from light gray tinged with rusty above and white below, to grizzly above and black below ; it is never pure black ; the ears are low and broad, and never white ; the hair is less coarse and stiff than in the preceding species. It is found chiefly in the middle states, rarely in southern New England ; it is rather a slow climber, and of inactive habits ; it becomes very fat in au- tumn, when its flesh is excellent. The species called fox squirrel in the western and south- western states (8. Lodomcianus, Harlan) has a very full and broad tail ; it is rusty gray above and ferruginous below. The common gray squirrel (8. CaroUnensis, Gmel., and S. migra- torius, Aud. and Bach.) is about 22 in. long, of which the tail is 12 in. ; the upper molars are permanently five. The general color is gray above and white below, with a yellowish brown wash on the back and sides ; the region behind the ears has usually a white woolly tuft ; there is a black variety, the S. niger of Godman. The ears are very high, narrow, and acute, the tail flattened, feet large, claws strong, thumb a rudimentary callosity; the palms naked, and soles mostly so in summer; whiskers longer than the head. It is found extensively over the United States, being much the smallest at the south. The young are four