2O VERTEBRATES : MAMMALS. 



the preceding apes and monkeys, approaching more 

 nearly ordinary quadrupeds. They are known as Dog- 

 headed Monkeys and Mandrills. 



CEBID.E, OR NEW-WORLD MONKEYS. This group corr- 

 prises the monkeys of the New World, in all ninety-one 

 species. They are characterized by a more or less rounded 

 head, by nostrils opening on the sides of the nose and 

 wide apart, by thirty-six teeth,* and in many cases by a 

 long prehensile tail, and by the absence of cheek-pouches 

 and callosities ; they are in general smaller and less fero- 

 cious than those of the Eastern Hemisphere, and as a 

 whole seem to be inferior to them. They inhabit almost 

 the whole territory from Central America to 35 or 38 

 south latitude. Only one species, however, is found west 

 of the Andes. 



The prehensile tail of these monkeys is capable of 

 being twisted firmly around branches of trees, and some 

 species are thus able to sustain the entire weight of the 

 body. The tail is also sensitive, and thus becomes both 

 an organ of feeling and prehension, enabling the pos- 

 sessor to obtain small objects which are in situations 

 where the hand cannot be inserted. 



i. Sapajous, or those with a prehensile tail. 



The Genus Mycetes Howlers is prominent among 

 the New-World monkeys, and found throughout the 

 whole length of the territory occupied by the Ameri- 

 can monkey tribes. Howlers have the head pyramidal, 

 and are provided with a vocal apparatus by which they 

 produce the loudest and most frightful yells or howls, 

 often making night hideous. These monkeys are mostly 

 of large size, three feet long, with a tail about as long 

 as the body, and they are more ferocious than any other 

 American species. 



The Genus A teles Spider Monkeys comprises those 

 which inhabit chiefly Brazil and Guiana, and which are 



* The Marmosets (see next page) have only thirty-two teeth. 



