174 GEOGRAPHICAL ZOOLOGY. [PART iv. 



development of the maxillary bones into strong lateral ridges 

 corresponds to the structure of the most typical baboons. This 

 species extends further east than any other quadrumanous 

 animal. 



FAMILY 4 CEBID^E. (10 Genera, jftf Species.) 



GENERAL DISTRIBUTION. 



The Cebidse, which comprehend all the larger American 

 Monkeys, differ from those of the Old World by having an 

 additional molar tooth in each jaw, and a broad nasal septum ; 

 while they have neither cheek-pouches nor ischial callosities, 

 and the thumb is never completely opposable. Some have pre- 

 hensile tails, especially adapting them for an arboreal life. They 

 are divided into four sub-families, Cebinae, Mycetinse, Pithe- 

 ciinse, and Nyctipithecinae. The Cebidse are strictly confined to 

 the forest regions of tropical America, from the southern part of 

 Mexico to about the parallel of 30 South Latitude. The distri- 

 bution of the genera is as follows : 



Sub-family, Cebinae. Cebus (18 sp.), is the largest genus of 

 American monkeys, and ranges from Costa Eica to Paraguay. 

 They are commonly called sapajous. Lagothrix (5 sp.), the 

 woolly monkeys, are rather larger and less active than the pre- 

 ceding ; they are confined to the forests of the Upper Amazon 

 Valley, and along the slopes of the Andes to Venezuela and 

 Bolivia. Aides (14 sp.), the spider monkeys, have very long 

 limbs and tail. They range over the whole area of the family, 

 and occur on the west side of the Equatorial Andes and on the 

 Pacific coast of Guatemala. Eriodes (3 sp.), are somewhat inter- 

 mediate between the last two genera, and are confined to the 

 eastern parts of Brazil south of the equator. The three last 

 mentioned genera have very powerful prehensile tails, the end 

 being bare beneath ; whereas the species of Cebus have the tail 



