728 MAMMALIA. 



developed in a fashion comparable to that which has occurred in the 

 case of the Australian Marsupials. Of fifty living species, thirty are 

 confined to Madagascar, and the lemurs are there exceedingly numerous 

 in individuals. Outside of Madagascar they only maintain a precarious 

 footing in forests or islands, and are usually few in number. The 

 absence of defensive weapons, the frequent slowness of movement, and 

 the feeble intelligence apparently make them unable to hold their own 

 against the more specialised carnivores. 



Order Anthropoidea {Syn. Simle). 



This order includes five families. 

 Family 5. Hominidae. Man. 



„ 4. Simiidae. Anthropoid Apes. ) Old World 



„ 3. CercopithecidEe. Baboons. j Gatarrhini. 



„ 2. Cebidse. American Monkeys. ( New World 



„ 1. Hapalidag. Marmosets. J Platyrrhini. 



The following characteristics are generally true : — 



The body is hairy, least so in man ; the dentition is 



diphyodont and heterodont ; the incisors do not exceed ? ; 



the molars are \ except in the marmosets, where they 



are - ; the axis of the orbit is directed forward, and the 



2 * ' 



orbit is completely closed off from the temporal fossa by 

 ingrowths of frontal and jugal meeting the alisphenoid ; the 

 clavicles are well developed ; the radius and ulna are never 

 united ; 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 rudi- 

 mentary ; the hallux is opposable except in man, and has a 

 flat nail except in the orang; the thumb is usually more 

 or less opposable ; the cerebral hemispheres have numerous 

 convolutions, and overlap the cerebellum ; the stomach is 

 simple except in Semnopithecus and its relatives, in which 

 it is sacculated, and there is a caecum which is often large ; 

 there are two mammas on the breast ; the uterus is simple ; 

 the testes lie in a scrotum; the penis is pendent; the 

 placenta is meta-discoidal, being developed by the con- 

 centration of the villi from a diffuse area into a well-defined 

 disc. 



Some of the characteristics in which the Anthropoidea differ from 

 Lemuroidea may be re-emphasised : the orbit is separated ' from the 



