EXTERNAL FORM OF THE MAN-LIKE APES. 745 



thighs the hairs are about one hundred and sixty millimetres long, and 

 here, as on the lower part of the leg, they tend outward, while on the 

 back of the foot they grow toward the toes. On the back, shoulders, 

 and on the thigh and leg, the bristles are slightly curved. This qual- 

 ity increases the general impression of shagginess and fleeciness which 

 is produced by the hairy coat of these creatures. The woolly hair 

 does not grow very thick, and is not much matted. 



The color of the hair not only differs on different parts of the body, 

 but also in different individuals. On the crown of the head it is of a 

 reddish-brown, or rarely of a decided brown or black. The hairs in 

 this region are sometimes dun-colored at the root, grayish-white in the 

 center, and brownish-red, shading into the dark-brown tip. The hair 

 on the lips is sometimes of a blackish-brown, sometimes whitish, or 

 both colors are found together. The hair growing at the sides of the 

 face is gray below, dark brown or almost black above. On the neck 

 and shoulders the hair is of a gray color at the root, and gradually 

 becomes lighter toward the tip. In the center it is brown, shading 

 into a lighter color at either end ; but this ringed form of color is not 

 universal. The tips of the hair are dark, sometimes brown or reddish. 

 The hair on the back, on the upper arms and thighs, is whitish or light 

 gray for half its length, with a blackish-brown ring toward the tip, 

 which is of a dark-gray color. Many of these hairs on the back have 

 two brown rings on them. The forearms, hands, shanks, and feet are 

 covered with hairs which are gray at the root, brownish gray, dark 

 brown, or black at the tip. Round the posteriors there is a circle of 

 white, gray, or brownish-yellow hairs, from ten to twenty millimetres 

 in length. In both sexes variations from the color of the coat here 

 described are not rare. It has been already observed that the brown- 

 ish-red color of the hair on the head is sometimes exchanged for 

 another shade. In many individuals the neck, shoulders, and back are 

 of a dark gray, brown, or even black color. In others the forearms, 

 hands, shanks, and feet are covered, like the rest of the body, with 

 gray and brown hair intermingled. 



The second species of anthropoid apes is the chimpanzee. In this 

 case also we must consider successively the aged and young male, and 

 the aged and young female animals. 



The full-grown chimpanzee is smaller than the adult gorilla. In 

 this species also the male is larger than the female. The chimpanzee 

 is, speaking generally, of a slighter build than the gorilla. 



The head of the aged male chimpanzee fundamentally differs from 

 that of the aged male gorilla, since the skull of the former has a de- 

 pressed crown, and the transverse occipital ridge is only faintly indi- 

 cated. Since the orbits are also less strongly developed than in the 

 aged male gorilla, and the spinous processes of the cervical vertebrse 

 do not assume the same elevated form which is characteristic of the 

 latter species, the countenance of the chimpanzee is not of a square 



