FIGURE 34. Left pectoral limbs of some aquatic reptiles: (a) leatherback turtle 

 (Dermachelys)\ (b) Geosaurus; (c) Clidastes (a moasaur) ; (d) Op- 

 thalmosaurus (an ichthyosaur) ; and (<?) Elasmosaurus (a plesiosaur). The 

 last four are redrawn from Williston. 



[211] 



