xm PHYLUM CHORDATA 473 



Family ii. Cebidce. 



Anthropoidea with the pollex not opposable, all the digits provided 

 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 is 



2133 



i. 2 c - i' P- 3' m - 3 = 



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

 (Calliihrix), Squirrel Monkeys (Chrysothrix), Spider-Monkeys (Aides), 

 and Capuchin Monkeys (Cebus). 



Family iii. Cercopithecidce. 



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 



2123 

 is i. ~> c. p p. s> rn. ^ = 32. The csecum is devoid of vermiform 



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 (Anthropopithecus), and Gorillas (Gorilla). 



Family v. Hominidce. 



Anthropoidea which differ from the Simiida) mainly in the more 

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

 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). 



VOL. II G G 



