780 MANUAL OF ZOOLOGY. 



hands. The spine shows a single curve, and articulates with 

 the back part of the skull. The canine teeth of the males are 

 long, strong, and pointed, but this is not the case with the 

 females. The structure, therefore, of the canine teeth is to be 

 regarded in the light of a sexual peculiarity, and not as having 

 any connection with the nature of the food. 



In this tribe are the Gibbons (Hyhbates), the Orang-utan 

 {Simla satyrtis\ the Chimpanzee, and the Gorilla. 



The Gibbons form the genus Hylobates, and they belong to 

 southern Asia and the Indian Archipelago. The anterior limbs 

 are extremely long, and the hands nearly or quite reach the 

 ground when the animal stands in an erect posture. There is 

 no tail, but there are natal callosities. The body is covered 

 with a thick fur. The sternum is wider than in the other 

 Apes, and the chin is better developed. One of the best 

 known of the Gibbons is the Siamang (Hylobates syndaJylus), 

 which has been sometimes regarded as making a nearer ap- 

 proach to Man than any other of the Monkeys. It is a native 

 of Sumatra. It is the largest of the Gibbons, and derives its 

 specific name from the fact that the index and middle toes of 

 the hind-foot are united to one another by skin as far as the 

 nail-joint. Another well-known species is the common Gibbon 

 (H. tor). 



In the Orang or " Mias'" (Simia satyrus) there are neither 

 cheek-pouches nor natal callosities, and the hips are covered 

 with hair. As in the Gibbons, the arms are excessively long, 

 reaching considerably below the knee when the animal stands 

 in an erect posture. The hind-legs are very short, and there 

 is no tail. When full grown the Orang stands about four feet 

 high. It never progresses with the help of a stick, or walks 

 erect at all, except along the branches of trees, supporting itself 

 by a higher branch, or when attacked. When young, the head 

 of the Orang is not very different from that of an average 

 European child; but, as the animal grows, the facial bones 

 become gradually produced, whilst the cranium remains in a 

 tolerably stationary condition ; great bony ridges are developed 

 for the attachment of the muscles of the jaws and face ; the 

 incisors project ; and ultimately the muzzle becomes as pro- 

 nounced and well-marked a feature as in the typical Carnivora 

 (fig. 453, A). The Orangs are inhabitants of Sumatra and 

 Borneo. They are arboreal in their habits, and form for them- 

 selves a sort of nest or shelter amongst the trees. The fore- 

 head is rounded, the cerebrum is greatly convoluted, and the 

 canine teeth of the full-grown males are very large. 



The genus Troglodytes contains the Chimpanzee (71 niger) 



