Xlll 



PHYLUM CHOHDATA 



557 



imier surfaces, and for the shortness of the pubic symphysis. In 

 the higher Apes some of these features are recognisable, though 

 less pronounced ; but in the lower the ilia are long and narrow, and 

 usually curved outwards ; in the Old-world Monkeys the tuberosities 

 of theischia are strongly everted and roughened for the attachment 

 of the ischial callosities. 



The tibia and fibula are well-developed and distinct in all. In 

 nearly all, the hallux, owing to the form and direction of the articu- 

 lation between it and the internal cuneiform, is opposable to the 

 other digits, converting the foot into a grasping organ. The 

 human foot (Fig. 1180) is distinguished from that of the other 



Alan. "" 



0?a«j 



Fig. 1180. — Foot of Man, Gorilla and Orang drawn the same absolute length, to show the 

 difference in proportions. The line a' a' indicates the boundary between tarsus and meta- 

 tarsus ; 0' h', that between the latter and the proxinaal phalanges ; and c' c' boLtnds the ends 

 of the distal phalanges, as. astragalus; ca. calcaneum ; sc. scaphoid, (After Huxley. ) 



Primates by the absence of this power of opposition and by 

 the relative length of the tarsus, which exceeds that of the 

 metatarsus. 



Digestive Organs. — Teeth are present in nearly all Mammals, 

 but in some they are wanting in the adult condition {e.g., Whale- 

 bone Whales and Platypus). In Echidna teeth are not present 

 even in the young. In some of the ./^nteaters teeth are developed 

 in the foetus and are thrown off m utero — the adult animal being 

 devoid of them. 



VOL. II 



M M 



