The Reign of RejytileB 



dinosaurs these bones are always separate, but 

 they are very much crowded together and 

 coTiie near uniting in a genus to w^hich Profes- 

 sor Marsh gave the name Ornitliomimus, bird- 

 mimic. The members of this genus, too, have 

 hollow bones and very bird-like claw^s, and are 

 mostly small, so that in many ways they resem- 

 ble birds. 



The last group of dinosaurs to be consid- 

 ered, the Predentata, were, as indicated by their 

 teeth and claws, all herbivorous, and it is easy 

 to see that the big, horny beak would be most 

 useful for cutting twigs and leaves. In their 

 day grasses had not appeared, and none of the 

 animals possessed such complicated grinding 

 teeth as are found in the horse and cow and 

 are especially adapted for fine vegetation. Still 

 the adaptation of the Predentata to a diet of 

 leaves and branches, and the general structure 

 of their skeleton, which shows them to have 

 been well fitted for life on land, gave them an 

 advantage over the great, marsh-haunting sauro- 

 pods, and they lived on through the Cretaceous. 

 Besides the extra bone in the lower jaw, all had 

 13 169 



