764 MAMMALIA. 



Order ANTHROPOIDEA (Syn. SIMILE). 

 This order includes five families. 



Family 5. Hominidse. Man. 

 ,, 4. Anthropomorphidse or Simi- ^ 



idae. Anthropoid Apes. [ Old World 

 ,, 3. Cercopithecidae. Baboons, I Catarrhina. 



etc. 



2. Cebidae. American Monkeys. \ New World 

 ,, i. Hapalidae. Marmosets. J Platyrrhina. 



The following characteristics are generally true :- 

 The body is hairy, least so in man ; the incisors do not 

 exceed 2 ; the molars are -^, except in the marmosets, 



where they are - ; the back teeth are bunodont, the premolars 



with two cusps, the molars usually with four ; the cranial 

 cavity is relatively large ; the axis of the orbit is directed 

 forward, and the orbit is closed off from the temporal fossa 

 by ingrowths of frontal and jugal meeting the alisphenoid ; 

 the lachrymal foramen is infra-orbital ; the clavicles are well 

 developed ; the radius and ulna move freely on one another 

 in pronation and supination ; the scaphoid, the lunar, and 

 usually the os centrale remain distinct from one another ; 

 there are usually five fingers and five toes, but the thumb 

 may be absent or rudimentary ; the thumb if present is 

 opposable except in marmosets ; the hallux is opposable 

 except in man ; the nails are almost invariably flat, except 

 in marmosets ; the cerebral hemispheres have in most cases 

 numerous convolutions, and usually cover the cerebellum ; 

 the stomach is simple except in Semnopithecus and its 

 relatives, in which it is sacculated ; there is a caecum which is 

 often large; there are two mammae on the breast; the 

 uterus is simple ; the testes lie in a scrotum ; the penis is 

 pendent ; the placenta is metadiscoidal, being developed by 

 the concentration of the villi from a diffuse area into a well- 

 defined disc. Most Anthropoidea are arboreal, gregarious, 

 uniparous, and tropical or sub-tropical. 



