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THE CHANGING GENERATIONS 



Fig. 28.5. One of the largest of the cotylosaurs. Bradysaurus, a South African pariasaur, 

 was 8 feet long and as heavy as an ox, though it retained the primitive form and posture. 

 Note the disproportionately small head, outbowed legs, and clumsy body. (Courtesy Chicago 

 Natural History Museum.) 



Fig. 28.6. A fossil ichthyosaur, or fish-lizard, Ichthyosaurus quadricissus, with imprint of 

 soft tissues around the skeleton. Length, 5 feet 8 inches. (Courtesy American Museum of 

 Natural History.) 



plesiosaurs were 8 to 10 feet, large ones up to 50 feet in length. They fed 

 upon fish, ammonites and other swimming creatures, as is shown by 

 remains found within their skeletons. The group arose in Triassic times 

 and persisted until the end of the Mesozoic era. 



The diapsid mosasaurs were as close an approach to the mythical sea 

 serpent as ever existed. They were huge marine lizards, some of them 40 



