230 THE GEOGEAPHY OF MAMMALS 



number about ten species, which are distributed over the 

 whole area occupied by the family as above described, 

 being most numerous, perhaps, in the great forests of 

 Amazonia. Closely allied to Ateles are the Woolly Spider- 

 Monkeys of the genus Brachy teles, which are confined to the 

 forests of South-eastern Brazil. They have been divided 

 into three species, but the prevailing opinion amongst 

 modern naturalists is, that these are really only varying 

 forms of one species. 



The typical genus Cebus, which follows next in the 

 series, numbers some eighteen or twenty species, many of 

 which, however, are very imperfectly discriminated. This 

 genus also has an extensive range, extending from 

 Nicaragua to Paraguay, but being most numerously re- 

 presented in Amazonia. With Cebus we close the first 

 and most highly organized group of the New World 

 Monkeys which constitute the first sub-family Cebid^e. 



The second sub-family of the Cebidre, the Mycetinge, 

 contains only the single genus Mycetes with about six 

 species, commonly known as Howlers, from their extra- 

 ordinary voices, produced by a specially modified vocal 

 organ. The Howlers have also a wide distribution in the 

 New World, one species, M. villosus, being found as far 

 north as Guatemala, whilst another. M, niger, occurs in 

 Paraguay. 



The third sub-family of American Monkeys contains 

 only two genera — the long and bushy-tailed Sakis (Pitltecia) 

 and the short-tailed Ouakaris (Brachyurus). Contrary to 

 what is the case in the previous sub-families, the generic 

 area of this group is much constricted, being confined to 

 the basins of the Orinoco and Amazon and to Guiana, which 

 is surrounded by them. The five or six known species of 



