EXTERNAL FORM OF THE MAN-LIKE APES. 747 



Fig. 5.— Eae of Chimpanzee. 



by the length of tlie 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 cal- 

 losities 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 gi-eat- 

 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 re- 

 sembles 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 



