84 The Alligator and Its Allies 



irregular bone, articulating with the ulna and the 

 ulnare; it is apparently connected by a long liga- 

 ment with the fifth metacarpal but does not actually 

 articulate with it. The centrale (ce) is a flattened, 

 partially ossified element between the radiale 

 and the first and second metacarpals. The distal 

 carpal bones are represented by two irregular, 

 partially ossified elements between the ulnare and 

 the third, fourth, and fifth metacarpals. 



The man us proper consists of five digits. The 

 metacarpals (m) are of about the same shape, but 

 vary in length and thickness; each consists of a 

 cylindrical shaft with a slight enlargement at each 

 end. The first digit or poUex has two phalanges, 

 the second has three, the third has four, the fourth 

 has four, and the fifth has three. The terminal 

 phalanx of each of the first four digits is poiated, 

 has a pair of lateral grooves, and is encased in a 

 large, homy claiv (cl). 



The Pelvic Girdle and Posterior Limb. The pelvic 

 girdle is described differently by Wiedersheim and 

 Reynolds ; the bone called by the former the pubis, 

 the latter calls the epipubis. The bone called by 

 Wiedersheim the pubis takes no part in the forma- 

 tion of the acetabulum; the pubis of Reynolds 

 helps form the acetabulum but is a very small, 

 unossified structure. Gadow also calls the lower 

 bone the epipubis. I shall follow Reynolds's 

 interpretation. 



The ilium (Fig. 28, i) is a heavy bone with 



