0KDE15S OF MAMMALIA. 359 



the animal can ])rogress in an erect or semi - erect posture. At 

 the same time the hind - feet are strictly prehensile, since the 

 thumbs are opposable to the other toes. The canine teeth of the 

 males are very long, strong, and pointed, but this is not the case in 

 the females. 



In this tribe are the Gibbons, the Chimpanzee, the Orang-outang, 

 and the Gorilla. The Gibbons form the genus Hylohates, and they 

 belong to Asia, India, and the Indian Archipelago. The anterior 

 limbs in these monkeys are extremely long, and the hands nearly or 

 quite touch the ground when the animal stands erect. The Orang- 

 outang (Simia) has no cheek-pouches, and the hips are covered with 

 hair. The arms are of excessive length, and the hind-legs very 

 short. When young, the head of the Orang-outang is not very 

 diiFerent from that of a child, but as the animal grows, the bones of 



Fig. 2;4.— A, Skull of the Orang-outang; B, Skull of a European adult. 



the face gradiially lengthen, whilst the skull remains much about 

 the same ; great bony ridges are developed for the attachment of the 

 muscles which act upon the jaws ; the incisors project ; the canine 

 teeth of the males become long and pointed, till ultimately the 

 muzzle becomes as pronounced and well marked as in the Carnivor- 

 ous animals (fig. 264, A). The only unquestionable species of Orang 

 is the Simia satyrui, which inhabits Sumatra, Borneo, and the other 

 larger islands of the Indian Archipelago. The Chimpanzee and 

 Gorilla both belong to Africa, and form the genus Troglodytes. 

 The Chimpanzee is a native of Western Africa, and has the arms 

 much shorter proportionately than in the Gibbons and Orangs. Still 

 they are much longer than the hind-hmbs, and reach below the 

 knees. The hands are naked to the wrist, and the face is also naked 



