MESOZOIC ERA: THE AGE OF REPTILES 



545 



ones. In a mummified specimen (Trachodon) found in Wyoming, 

 the epidermis, which is covered with flat, bony scales, is seen to be 

 extremely thm and the markings exceedingly fine and delicate for an 









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Fig. 508. — Restoration of the herbivorous, duck-billed dinosaur, Trachodon. 

 (Restoration under the direction of Professor Osborn. Copyright, American Museum 

 of Natural History.) 



animal of such dimensions (Fig. 510). The same specimen shows 

 that the fore feet were webbed, the skin reaching beyond the fingers 

 and forming a sort of paddle. Since these animals had strong, 

 powerful hind legs and were without armor, it is evident that their 

 existence depended upon their ability to escape their carnivorous 

 enemies by speed. 

 Some (Camptosaurus 

 and Iguanodon) ap- 

 parently lived on 

 the dry land, while 

 others (Trachodon) 

 were amphibious. 

 The latter were able, 



Fig. 509. — Portion of the lower jaw of Trachodon. 

 The numerous teeth form a kind of pavement. (After 

 Gilmore.) 



when on land, to run rapidly, and when in the water to swim, per- 

 haps, with the speed of the crocodile, as is indicated by the great, 

 flattened, crocodile-like tail. 



Armored Dinosaurs (Armored Predentata). — The reptiles of 

 this group were of two very different types. A representative of 



