SAUROPTERYGIA 83 



however, was not flat like the under shell of a turtle, but rounded 

 from side to side. 



Fig. 36. — Pelvic girdle from above of Trinacromerum osbomi, an Upper Cretaceous 

 plesiosaur: p, pubis; is, ischium; il, ilium. 



Many of the characteristics of the limbs of the plesiosaurs are 

 peculiar to themselves; others they had in common with other 



