SAVROPTERYGIA 



83 



however, was not fiat like tlie under siiell of a turtie, but rounded 

 from side to side. 



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

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



Many of tlie cliaracteristics of tlie limbs of the plesiosaurs are 

 pecuhar to themselves; others they had in common with other 



