lyS 



THE OSTEOLOGY OF THE REPTILES 



pterodactyls resulted in a maximum of firmness with but little mobil- 

 ity, 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 char- 

 acteristic 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- 



