VERTEBRATA. 277 



are the lowest of the monkey tribe. 2. Platyrrhines, or 

 Monkeys with simple sub-terminal nostrils, as the Spider- 

 monkeys. These are South American, or New- World 

 monkeys, with prehensile tails. The Howling-monkey 

 (Mycetes) has a curious modification of the larynx in the 

 shape of a bony drum attached to the hyoid bone, with 

 which it produces discordant shrieks. 3. Catarrhines, or 



FIG. 170. Quadrumana. Baboons. i. Mandrill, (Papio maimon.) 2. Chacma, (Chac- 

 ma Porcarius.) Monkeys. 3. Mona, (Cercopithecus mono,.} 4. Howler, (Mycetes.) 

 5. Spider, (A teles.) 



monkeys with oblique nostrils, approximating below, 

 separating above, as the Gorilla and Chimpanzee. This 

 division includes the highest, or anthropoid Apes of the 



Old World. They are all four-thumbed. The tail is not 

 24 



