Page:Popular Science Monthly Volume 28.djvu/764

744 this enlargement of the neck was present in a marked degree. In still younger individuals, however, under a year old, in which the spinous processes of the vertebræ have not yet been developed, there is no such enlargement, but, on the contrary, this region of the neck takes a concave form.

In conformity with the smaller size of the body, the shoulders, arms, and thighs of the adult female are smaller than those of the full grown male, but they are still very powerful. While giving suck, the breasts of the female are swelled in the form of a half-cone, instead of assuming the convex shape which is observed in many European women, and still more frequently in those of the negro, Indian, and South Sea races. The nipple is cylindrical rather than conical in shape, and covered with finely wrinkled black skin, which is sometimes hard and horny. When not giving suck, the breasts hang slackly down, like short empty pouches.

In a young female the cranium is rounded, and the face is only slightly prominent. In aged specimens, especially in those of the male sex, there is a somewhat typical prolongation of that part of the face which lies between the eyes and the end of the nose, and this is to a slight extent apparent in the young female. Variations in form and in the extent of the prolongation are, however, apparent even at this early period. The trunk and limbs are more slenderly built than in a male of the same age.

The hairy coat of the gorilla consists of long, thick, straight or stiffly curved bristles, and also of shorter, thinner, and curled woolly hair. On the crown of the head the hair is somewhat stiff from twelve to twenty millimetres in length, and it becomes erect under the influence of anger. While the sides and fore part of the chin are only clothed with short, stiff hairs, they grow thickly on the back part of the chin, like a beard or forelock. The hairs which turn outward from the sides of the face and on the neck are thirty or more millimetres in length. On the shoulders the hair is from one hundred and thirty to one hundred and fifty millimetres long, hanging down on the upper arms and the back. In the middle of the upper arm the hair is from fifty to seventy millimetres long, growing downward as far as the bend of the elbow. At this point it generally begins to grow in an upward direction. On the back of the forearm it again grows downward. In the middle of the forearm, on its inner side, a parting of the hairs takes place, as one portion goes in front of the radius, while the other portion turns behind the ulna. On the back of the wrist a tuft of curved hair turns upward; a middle tuft goes directly back; and the lower tuft, also curved, turns outward. On the back of the hand the hairs turn toward the fingers. On the breast and belly the hairs are shorter and grow more sparsely. On the breast their direction is, as a rule, upward and outward. On the belly they converge from the ribs toward the center and the navel. On the