THE VERTEBRATES: MAMMALS 



257 



are always long-tailed, the tail being frequently prehen- 

 sile. They include the howling, squirrel, spider, and ca- 

 puchin monkeys common in the forests of tropical South 

 America. The catarrhine monkeys have the nose-septum 

 narrow and the openings of the nostrils directed forwards, 



Fig. 134. "Bob," a monkey of the genus Cercopithecus. (Photograph 

 from life by D. S. Jordan.) 



and the tail is wanting in numerous members of the group. 



They include the baboons, gorillas, orang-outangs, and 



chimpanzees. These apes have a dentition approaching 



that of man, and in all ways are the animals which most 



nearly resemble rnan jn physical character, 



