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 manus 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 pollex 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 pointed, 
has a pair of lateral grooves, and is encased in a 
large, horny claw (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 dium (Fig. 28, 1) is a heavy bone with 
