Page:The Osteology of the Reptiles.pdf/196

pterodactyls resulted in a maximum of firmness with but little mobility, which was not needed in the volant hand.

The carpus of the Pseudosuchia and Phytosauria is practically unknown.

Fig. 144. Chelonia, Pleurodira: Thalassochelys, right front and hind legs.

Marked modification in the structure of the carpus is also characteristic of the Lacertilia (Fig. 140 c). There are but three bones in the proximal row, which may also be interpreted as the radiale, ulnare, and pisiform. No intermedium is visible in the various forms examined. It is reported to be present only in the family Lacertidae. A centrale is usually present, though sometimes small. The first cen-