THE ORIGIN OF MAN 63 



food that we do not know the precise nature of 

 the animal's diet. It is thought however that 

 some plant that existed in great abundance at 

 that time formed the chief food supply and 

 which was not masticated but detached by the 

 claws and teeth and swallowed intact. None of 

 the Sauropoda were small, the Brontosaurus be- 

 ing of representative size. They inhabited the 

 sluggish waters of an imperfectly drained coun- 

 try, which supported their huge bulk and sup- 

 plied the plants upon which they fed. The other 

 great dinosaurian race was exclusively plant feed- 

 ing and bore within the mouth a wonderful bat- 

 tery of teeth. The teeth were few and simple at 

 first but becoming as time went on more numer- 

 ous until in Trachodon the dental battery con- 

 tained no fewer than two thousand teeth. 



These predentate dinosaurs, as they were 

 called from the peculiar toothless bone that united 

 the two halves of the lower jaw, soon differen- 

 tiated into two distinct races, the unarmored bi- 



