Ii8 Vertebrata. 



CHAPTER XIX. 



MONKEYS. MAN. 



70. Order 16, Primates. This, the last and 

 highest order of mammals, includes the most highly 

 organised members of the entire animal kingdom 

 the monkeys, apes, and mankind. They all possess 

 opposable thumbs on some of the extremities, and 

 (except among the marmosets) flat nails in place of 

 claws. The face is mostly naked though fringed with 

 hairs. The teeth are of three kinds and thirty-two 

 in number, the formula being usually 



2 - 2 I - 1 2 - 2 3 - 3 



They have the highest proportional development of 

 brain of all animals, and the fore-limbs are chiefly set 

 apart to wait on the head. There are four sub-orders 

 included: 



1. The marmosets of South America, gregarious 

 small monkeys of a squirrel-like habit, which have 

 sharply tubercled teeth, claw-like nails on all the 

 digits, except the great toe, which alone bears a flat 

 nail. The long fur-clad tail is incapable of grasping, 

 and the thumb is scarcely opposable. 



2. The American monkeys, which differ from all 

 others in having an additional premolar tooth on 



each side of each jaw (P ^ *). They have for the 



o 3 

 most part prehensile tails, and the thumb of the 



