THE JURASSIC PERIOD 721 



brain had less diameter than its spinal cord. "The task of provid- 

 ing food for so large a body must have been a severe tax on so 

 small a head." The largest of all known dinosaurs was Brachio- 

 saurus, of which the femur measured more than two meters in length 



Fig. 492. A carnivorous dinosaur, Ceratosaurus no.sicornis, about }4o natural 

 size, i. e., length about 17 feet; from the Como beds, Colorado. (Res- 

 toration of skeleton by Marsh.) 



Fig. 493. An herbivorous dinosaur, Brontosaurus (Apatosaurus) . Res- 

 toration of skeleton by Riggs, nearly 60 feet long; from Wyoming. 



(80 J inches) 1 . There were several other genera of similar nature, 

 and of bulk only inferior to these monsters. 



The typical ornithopod (bird-footed) dinosaurs were bipedal in 

 habit, like the carnivores. On the hind limbs there were usually 



1 Riggs, Amer. Jour. ScL, 1903. 



