XVI.] GENERAL CHARACTERS. 259 



The first metacarpal is shorter, though somewhat broader 

 than any of the others. It is articulated in a different plane 

 from them, its palmar surface facing towards the ulnar side 

 of the hand, and it is capable of a considerable range of 

 movement. The other four metacarpals are nearly equally 

 developed, diminishing slightly from the radial to the ulnar 

 side ; their shafts are slender and rather compressed, 

 especially towards the pahriar aspect; but they enlarge at 

 each extremity, particularly at the rounded distal end or 

 head. They are so articulated with the carpus as to allow 

 of very little motion. The phalanges are of the normal 

 number to each digit, all broad, convex on their dorsal, and 

 flattened or slightly hollowed on their palmar, side. The 

 proximal is the largest, and the ungual the smallest. The 

 latter is flattened and slightly expanded or spatulate at its 

 terminal portion. Those of the first digit or thumb are 

 stouter than any of the others, those of the fifth digit (little 

 finger) are the most slender. The third digit is the longest, 

 the second and fourth somewhat shorter and nearly equal, 

 the fifth considerably shorter, and the first still more so. 

 Sesamoid bones are only developed, behind the metacarpo- 

 phalangeal joint of the pollex. 



In the other Primates, the manus is generally longer and 

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

 thumb is less developed and less freely moveable. In the 

 genera Troglodytes and Simla, 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 additional bone {os cen- 

 trale, Gegenbaur, Fig. 87, ce) is present in all, except in the 

 Gorilla and Chimpanzee, and some of the Lemurs. This 

 is considered by some anatomists to be a dismemberment 

 of the scaphoid. The pisiform is present in all, and gene- 



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