PREHISTORIC ANIMALS 



427 



mighty, and aavpo<i, lizard), contained many genera, some of 

 which were among the largest land animals that have ever 

 existed. In some the skin appears to have been naked, in 

 others there was a bony external skeleton sometimes provided 

 with spines. The shape of the body varied much. One of the 

 most familiar genera was Iguanodon (Fig. 406), which had rela- 

 tively small fore feet but large hind legs and a well-developed 

 tail, and it appears to have rested usually, much like a kangaroo, 



Fig. 406. Iguanodon bemissartensis, one sixtieth natural size, co, coracoid ; /s, ischium ; 

 /.pubis (pectineal process); />/>, post-pubic process (pubis); I-IV, I-V, digits. (After 

 Dollo, from Parker and Haswell's Text-book.) 



on its hind legs and tail ; the total length of the body was from 

 fifteen to eighteen meters. It appears to have been entirely 

 herbivorous, feeding largely on the foliage of trees. Another 

 genus, Atlantosaurus, belonging to this same group, contains 

 some gigantic species. One found in Colorado was from fifteen 

 to eighteen meters long, and when erect at least nine meters 

 in height; it was an herbivorous land animal. The Dinosauria, 

 like the Ichthyopterygia, are found in the Triassic, Jurassic, and 

 Cretaceous. 



The Pterosauria (Gr. irrepov, wing, and aavpos, lizard) consti- 



