XXIV 



MONKEYS, APES, AND MEN 



1. Common origin of Old World monkeys, apes, and men 



The seventeen living genera of Old World monkeys, apes, and men 

 are sometimes classified together as Catarrhina because of the common 

 characteristics in which they contrast with the New World monkeys. 

 Perhaps this union is justified and the Catarrhina is a monophyletic 

 group, with a common ancestor in the late Eocene. However, these 

 creatures are obviously much more diverse than the New World 

 monkeys and have entered a wide variety of habitats. The Old World 

 monkeys proper, the super-family Cercopithecoidea, diverged very 

 early from the apes and men (Hominoidea). Some distinguish between 

 the monkey and ape-human branches of the stock, by calling the 

 former cynomorphs, the latter anthropomorphs or hominoids. Others 

 regard all three groups as widely separate. However, the earliest 

 definite catarrhine known, *Parapithecus of the Oligocene, is close 

 to the origin of all three groups, so we may reasonably keep them 

 together. 



2. Old World monkeys, Cercopithecoidea 



The cercopithecid or Old World monkeys do not differ very 



strikingly in general habits and organization from the monkeys of the 



New World, though they are mostly larger. We must conclude either 



that the two groups have made many changes in parallel or that in the 



Eocene there were already animals with the good senses, active brains, 



and skilled movements of the monkeys. The distinguishing features of 



the Old World types are rather trivial, for instance they sit upon 



ischial callosities, surrounded by naked and often highly coloured skin, 



which becomes enlarged in the female before ovulation. There are 



often cheek pouches in which to store food, usually complicated 



laryngeal sacs, a bony tympanic tube, and never a prehensile tail. The 



great reduction of the olfactory turbinals leaves the nostrils close 



2.1.2.3 

 together and pointing downwards. The dentition is reduced to - — , 



the upper molars carry four cusps, and the lower four except for the 

 last, which has five (Figs. 383 and 396). The diet of the more gener- 

 alized cercopithecids is omnivorous, including insects, lizards, eggs, 



