68 COPE 



The Dinosauria embrace two suborders, as follows : 

 Pubic elements directed downwards; Saurischia^. 



Pubic elements directed backwards; Orthopoda. 



The Saurischia were mostly of carnivorous habits, while 

 the Orthopoda were herbivorous. Both suborders com- 

 mence in the Trias, and close with the end of the Postcre- 

 tacic. To the Saurischia belong two families, the 

 Cetiosauridse and the Megalosauridse, the former supposed 

 to be herbivorous, the latter carnivorous. The former have 

 robust inferior pelvic bones, and teeth vi^ith spoon-shaped 

 crowns. The latter have long, slender pubis and ischium, 

 and sharp, knife-shaped teeth. 



To the Cetiosauridse belong the largest known Vertebrata 

 with ambulatory legs ; the Camarasaurus supremus Cope 

 measuring seventy feet in length, and the Amphicoelias 

 fragilissimus Cope being considerably larger. These crea- 

 tures had the dorsal vertebrse hollow, and probably pene- 

 trated in life by branches from the lungs, while the tail 

 vertebrse and limb bones are solid. The former served as 

 floats and the latter as anchors as they walked on the sea 

 bottom. This family is only known from the Jurassic of 

 Europe and North America (Fig. 22). The Megalosauridse 

 ranged throughout all Mesozoic time. Some of the species 

 were quite small, and others were gigantic, being the most 

 dangerous carnivorous animals that ever existed. Many of 

 them were of kangaroo-like form, and in some of them the 

 vertebrse were mere hollow shells. In most of them the 

 limb bones were hollow. 



