XIII 



PHYLUM CHORDATA 487 



Family ii. Cebidce. 



Anthropoidea with the pollex not opposable, all the digits pro- 

 vided with flat nails ; without cheek-pouches or ischial callosities ; 

 with a broad nasal septum, and without bony external auditory 

 meatus. The tail is sometimes prehensile. The dental formula 



This family includes the Howling Monkeys (Mycetes), Tee-Tees 

 (Callithrix), Squirrel Monkeys (Chrysothrix), Spider-Monkeys 

 (Aides), and Capuchin Monkeys (Ccbus). 



Family iii. Gercopithecidce. 



Anthropoidea with the pollex, when present, opposable ; with or 

 without cheek-pouches ; with ischial callosities ; with a narrow 

 nasal septum, and a bony external auditory meatus. The tail is 

 not prehensile. The sternum is narrow. The dental formula 



o -i sy q 



isi. -, c. -,p. -,m.- =32. The caecum is devoid of vermiform 

 2 L 2 o 



appendage. 



This family includes the Baboons (Cynocephalus) and Macaques 



(Macacus). 



Family iv. Simiidce. 



Anthropoidea with the pollex opposable ; without cheek-pouches ; 

 usually without ischial callosities ; with a narrow nasal septum, and 

 a bony external auditory meatus. The pectoral limbs are much 

 longer than the pelvic. The caecum has a vermiform appendage. 

 The centrale of the carpus is sometimes absent. The dental 

 formula is the same as that of the preceding family. 



This family includes the Gibbons (Hylobates), Orangs (Simia), 

 Chimpanzees (Anthropopitkecus), and Gorillas ( Gorilla). 



Family v. Hominidce. 



Anthropoidea which differ from the Simiidse mainly in the more 

 perfect assumption of the erect posture, co-ordinated with altera- 

 tion of the curvature of the spine, and with the more complete 

 adaptation of the hind-limbs to bearing the weight of the body ; 

 in the absence of the power of opposition in the hallux, and its more 

 complete development in the pollex ; in the greater length of the 

 hind as compared with the fore-limbs ; in the smaller size of 

 the canine teeth; and the much greater size and complexity of 

 the brain. 



This family includes only the Human Species (Homo sapiens). 



