82 MIOCENE FAUNA. 



species*. For this Gervais has proposed to found a distinct 

 extinct genus (Pliopithecus) , whilst Rutimeyer adheres to the 

 opinion first expressed by Lartet, that it cannot be separated 

 from the Indian gibbons (Hylobates). At any rate, these tail- 

 less, long- armed apes are the animals most nearly allied to it. 

 With the orang-outan, the chimpanzee, and the gorilla they 

 constitute the most highly developed of the Quadrumana. Half 

 a dozen species are known; arid these inhabit the Sunda Islands, 

 Siam, and Hindostan : they attain a height of from 1 to 3J feet. 

 According to Riitimeyer, the Swiss fossil gibbon (Hylobates an- 

 tiquus, Lart., sp.) is most nearly related to the siamang (H. 

 syndactylus, Ram., sp.) of Sumatra t, an ape which, according 

 to Lartet and Vrolik, approaches in its osteology more closely 

 to man than either the chimpanzee or the orang. It will there- 

 fore be of interest to learn something as to its mode of life and 

 peculiarities ; for it is very probable that in these respects its 

 ancient relative (which, so far as Prof. Heer knows, was the 

 most highly organized animal of its time) resembled it. 



Fig. 324 represents this black-haired animal, which is 3J feet 

 in height when full-grown, and therefore about one fifth larger 

 than the extinct species. Duvaucel relates J t{ that the siamang 

 is very common in the forests of Sumatra." " Usually," he 

 observes, " we find the siamangs collected into numerous troops, 

 guided, it is said, by a chief, whom the Malays regard as invul- 

 nerable, no doubt because he is stronger, more active, and more 

 difficult to get at than the others. Thus united, they salute the 

 sun at its rising and setting with dreadful cries, which may be 

 heard at a distance of several miles, and which nearly stun a 

 person even when they do not cause fear. It is the morning- 



* Dr. Biedermann has separated it (under the name of Pliopithecus platyodori) 

 from the French species, because the molar teeth are a little broader ; but the 

 specimen obtained by Lartet is a lower jaw, and that from Elgg is an upper 

 jaw; and it is found that, in the existing gibbons, the molars of the upper 

 jaw are broader than those of the lower. 



t The fossil species is distinguished, according to Riitimeyer, by more 

 massive and closer square teeth, by having comparatively larger middle 

 incisors in the upper jaw, and consequently larger lateral incisors in the lower 

 jaw, and by its smaller general size. 



t See F. Cuvier, l Histoire Naturelle des Mammiferes,' by Geoffroy and F. 

 Cuvier. 



