AQUATIC REPTILES 



207 



new characters. Propulsion through the water was rather by 

 means of the paddles than by the combined lateral body-and- 



FiG. 84. Convergent Forms of Aquatic Reptiles of Different Origin. 



Lariosaurus (left), the Triassic ancestor of the plesiosaurs from northern Italy, and 

 Mesosaurus (right), from the Permian of Brazil and South Africa, representing another 

 extinct order of the Reptilia, the Proganosauria. Drawn by Deckert after McGregor. 



tail motion seen among the ichthyosaurs, because all plesiosaurs 

 exhibit a more or less abbreviated tail and a more or less 

 broadly depressed body. It is also significant that the fore 



Fig. 85. A Plesiosaur from the Jurassic of England. 



Skeleton of Cryptodcidus oxonicnsis seen from above. Mounted in the American Museum 



of Natural History. 



