608 General and Applied Biology 



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Fig. 315. — Three enormous dinosaurs (Gr. deinos, terrible; sauros, lizard), 

 extinct reptiles of the past. Diplodocus was over eighty feet long and weighed 

 forty tons; Brontosaurus was over sixty-five feet long; Brachiosaurus was about 

 eighty feet long. (From Atwood: A Concise Comparative Anatomy, The C. V. 

 Mosby Co.) 



Fig. 316. — Pleistocene tar pool near Los Angeles, Calif., with entrapped ani- 

 mals. The elephant and wolves are caught while the saber-toothed tiger is about 

 to suffer the same fate. (From Cleland: Physical and Historical Geology, pub- 

 lished by the American Book Company.) 



