572 



COLLEGE ZOOLOGY 



6. Prehistoric Reptiles 



Sixteen of the twenty orders of reptiles are known only from 

 their fossil remains embedded in the earth's crust. Three of 

 these orders will serve to give a general idea of the nature of the 

 extinct reptiles. 



Fig. 467. — Fossil reptiles. A, Bronlosaurus excelsus. B, Stegosaurus 

 ungulaius. C, Ceratosaurus nasicornis. (A, B, from Sedgwick's Zoology, 

 after Marsh; C, from Zittel, after Marsh.) 



