Page:Popular Science Monthly Volume 28.djvu/767

Rh by the length of the last phalanx, the third is a little longer than the first, and the fourth is again shorter. A web, which reaches to the middle of the first row of phalanges, stretches between the bases of the four fingers. There are horny callosities on the back of the hand of the aged male, since the chimpanzee, like the gorilla, supports himself on the backs of his closed fingers. The fingers are laterally compressed, but slightly arched on the back of the hand, and more decidedly so on the palm, A net-work of furrows covers the back of the hand, and these are more deeply impressed on its palm. The thumb is separated from the palm by a distinct furrow; and from four to six furrows of varying depth cross the center of the palm. The finger-nails are short, wide, and arched, very convex at their free edges.

In the aged male the sides of the belly are compressed, the thighs are broad and muscular, and somewhat flattened both on the inner and outer sides. The knees are rather prominent, the shanks are somewhat laterally compressed, and the calf of the leg is very slightly developed. As in the gorilla, the long, wide feet have a thumb-like formation of the great-toes, which are of considerable size. They extend, when drawing anything toward them, as far as the second phalanx of the second toe. The four other toes are more slender, and only a little longer than the great-toe. The heel is but slightly developed, and slopes away below. The joint between the first phalanx of the great-toe and the first metatarsal bone is marked by an angular projection on the inner edge of the foot. The back of the foot is very slightly convex. The last phalanx of the great-toe is very much sloped off on its upper surface, but this is less apparent in the other parts of this member. The last phalanges of the other laterally compressed toes are strongly arched on the under surface. Considerable convexities may also be observed under the metacarpo-phalangeal joint of the great-toe, and under its last phalanx. The shape of the toe-nails resembles that of the fingers. Large callosities are not unfrequently found on the backs of the toes, since the animal sometimes supports himself on these parts. A connective web is found between all the toes, except the great-toe and its neighbor, but it does not extend so far as that between the roots of the fingers.

Although the young male chimpanzee is distinguished from the aged male of the same species by differences in the structure of many