FAMILY CEBLDJE. AMERICAN MONKEYS. 169 



cheek-pouches and thumbs of the typical Monkeys ; whilst the 

 Macaques are equally far from possessing the stoutness of build 

 and the muscular energy, which characterise the true Baboons. 

 On the other hand, in Africa, where we find but a single 

 species of Ape, the Monkeys and Baboons are most abundant, 

 and their characters most fully displayed. The only African 

 genus that is deficient in the peculiarities of its tribe, is that of 

 Colobus, which seems to represent in Africa the Semnopithecus 

 of Asia ; and this bears a very small proportion, in the number 

 of its species, to the typical Monkeys and Baboons. Lastly, it 

 is curious to observe that, whilst all the African Simiadse, save 

 the Chimpanzee, possess cheek-pouches, these do not exist in 

 any of the Asiatic species, except a few Cercopitheci, and the 

 Macaques. 



158. FAMILY CEBID^:. This family includes all the American 

 Monkeys ; which differ from those of the Old World in several 

 particulars, besides those already stated ( 146). The thumb of 

 the fore-hands is never opposable to the fingers, and is very 

 frequently wanting. The callosities and cheek-pouches are 

 altogether absent. The tail is usually of considerable length, 

 never wanting, and often prehensile (that is, capable of laying 

 hold of branches &c.,) especially in the species that are destitute 

 of thumbs. In all but the Marmozets, there is a third bicuspid 

 molar on each side ; making the molars in all ^, instead of 

 Eg ; and bringing the total number of teeth to 36, instead of 32, 

 as in Man and the SimiadaB. A very obvious and simple cha- 

 racter, which is constant in each group, but the connection of 

 which with their general organisation seems by no means evi- 

 dent, serves to distinguish the Cebidae from the SimiadaB ; the 

 apertures of the nostrils in the former are directed laterally, or 

 outwards ; whilst in the latter they are directed downwards or 

 forwards, according to the position of the head. The Cebidse 

 are exclusively confined to the warmer regions of the New 

 World ; so that, although the species are numerous, their extent 

 of territory is far more limited than that occupied by the Old 

 World Monkeys. They inhabit the northern portion of South 

 America, from the Caribbean Sea, to about the twenty-fifth 



