378 VERTEBRATE ZOOLOGY 



snout, long tongue, and strong claws characteristic of this habitus. 

 The skin is very thick and is covered with sparse hair. 



SECTION B. PRIMATES (MAMMALS WITH "NAILS") 



ORDER 9. PRIMATES (LEMURS, MONKEYS, APES AND MAN). The 

 traditional position allotted to the primates is the last and highest or- 

 der of mammals, but it has come to be realized that the group is on 

 the whole more generalized than several other orders, and in point of 

 specialization belongs to a division just above that rather primitive 

 section, Unguiculata. The primates may be defined as primarily 

 arboreal animals with prehensile limbs; with thumb and great toe 

 shorter than the other digits and more or less opposable to the latter; 

 with plantigrade walking position of the feet; with terminal, flat- 

 tened " nails" instead of claws; with hair covering the entire body 

 except the palms and soles and parts of the face; with a single pair of 

 pectoral mammae; with the eyes directed anteriorly instead of later- 

 ally; the eye orbit completely surrounded with bone; a clavicle always 

 present; the stomach simple; and the brain unusually large and well 

 convoluted. 



Probably the best among many classifications of the primates is 

 that of W. K. Gregory: 



Sub-Order 1. Lemur oidea (lemurs or " half-apes"). 

 Sub-Order 2. Anthropoidea. 



Series 1. Platyrrhini (New World Apes). 

 Family 1. Hapalidse (Marmosets). 



" 2. Cebidse (capuchins, howler monkeys, spider 



monkeys, etc.). 

 Series 2. Catarrhini (Old World Apes and Monkeys). 



Family 3. Cercopithecidee (monkeys, baboons, macaques, 



etc.). 



" 4. Simiidae (man-like or anthropoid apes). 

 " 5. Hominidae (men). 



Sub-Order 1. Lemuroidea (Lemurs). The lemurs (Fig. 194, A) are 

 much the most ancient and the most generalized of the primates, and 

 therefore show less wide departures from the unguiculate mammals 

 than do the anthropoids. They are exclusively arboreal, mostly 

 nocturnal, and extremely timid and retiring. In appearance they 

 strike one as intermediate between a squirrel and a monkey. The 



