THE MANUS. 



[CHAP. 



narrower than in Man, and as a general rule the first digit or 

 thumb is less developed and less freely movable. In the 

 genera Troglodytes and Simia, as in Man, the proximal 

 surface of the carpus articulates with the radius alone, in all 

 others it articulates also with the ulna. The scaphoid and 

 lunar bones are always distinct. An os centrale, (Gegen- 

 baur, Fig. 92, ce) is present in all, except in the Gorilla and 

 Chimpanzee, and some of the Lemurs. Where it is wanting 

 as an independent bone it probably has become fused with, 

 and then forms part of, the scaphoid. The pisiform is 

 present in all, and generally of a more elongated form, and 

 more salient than in Man : and there is usually a small 



FIG. 92. Bones of the carpus of a Baboon (fyiiocephalus anubis), J. s scaphoid ; 

 / lunar ; c cuneiform ; p pisiform ; ce central ; rs radial sesamoid ; tin trapezium ; 

 td trapezoid ; in magnum ; it unciform ; I v the metacarpals. 



rounded radial sesamoid (rs) articulating movably to the 

 border of the scaphoid and trapezium, and connected with 

 the tendon of the flexor carpi radialis. 



In the Potto (Perodicticus) there is an additional bone on 

 the palmar side of the carpus, an ossification in the ligament 

 connecting the palmar processes of the trapezium and 

 unciform bones, and forming with these processes a com- 

 plete bony ring, through which the flexor tendons pass. 1 



1 Mivart, " On the Appenclicular Skeleton of the Primates ; " Phil. 

 Trans. 1867. 



