GORILLA, CHIMPANZEE, BABOONS. 397 



grees on either side of the Equator, or the forest region drained by 

 the Gaboon, Muni, Fernand-Vaz, and Ogowai rivers. Much uncer- 

 tainty still remains as to the number of species of chimpanzee, but 

 most naturalists seem inclined to unite all the variously designated 

 forms, either actually found living or reported to be such, into a 

 single species, Troglodytes niger, whose habitat extends from the 

 west coast (Gambia — Benguela) through the heart of the continent 

 to the central lake region. 



The Asiatic anthropoid apes are the gibbons (Hylobates) and 

 orang (Simia satyrus), the latter restricted to the forests of the 

 islands of Borneo and Sumatra. The gibbons, or long-armed apes, 

 which probably comprise a dozen or more species, are confined to 

 South-Eastern Asia, and some of the larger islands of the Eastern 

 Archipelago. On the continent they range from the Brahmaputra 

 River, in Assam, to the Malay Peninsula, and eastward to the region 

 about Canton, China (Hylobates pileatus); the Chinese species is 

 also found in the island of Hainan. The better-known forms are the 

 siamang (H. siamanga), the largest member of the genus, from Su- 

 matra, hoolock (H. hoolock), the most northern form (Assam, Ben- 

 gal), and lar (H. lar), from Siam, the Malay Peninsula, and Su- 

 matra. 



Of the non-anthropoid Quadrumana of the Old World the most 

 numerous in point of species are the dog-apes (Cynopithecinse) — 

 green-monkeys, macaques, drills, baboons, &c. The long-tailed 

 forms of the genus Cercopithecus are exclusively African, and com- 

 prise all the more graceful monkeys of the continent that have been 

 variously designated guenons, green-monkeys, and white-nosed 

 monkeys. Collectively, they range over the greater part of the 

 tracts included between the Gambia and Congo Eivers on the west 

 and Abyssinia and the Zambezi on the east. The mangabeys, some- 

 times separated as a distinct genus (Cercocebus), are West African, 

 as is also the talapoin (Miopithecus talapoin). Almost equally dis- 

 tinctive of the African region are the dog-faced baboons of the 

 genus Cynocephalus, which have a very general distribution 

 throughout the continent, extending also into the adjoining tracts 

 of Asia (Arabia). Among the better-known members of this group 

 are the mandrill and drill (C. maimon or mormon, and C. leuco- 

 phaaus), both from the west coast (Guinea) ; the baboons proper 

 (C. babuin), whose habitat extends from Abyssinia and Kordofan 



