Io8 THE AMERICAN NATURALIST. [Vol. XXXVIII. 



I. Order Procolophonia Seeley. 



This includes the most primitive of the Diaptosauria ; those 

 closest to the Cotylosauria, and distinguished by the entire 

 absence of lateroemporal fen- 

 estrae/ by the persistence of 

 the epiotics and auditory 

 notch of the cotylosaurs, 

 and other very primitive char- 

 acters. These animals are 

 thus far recognized in the 

 Permian of South Africa 



2. Order Protorosauria 

 Seeley. 



This land group includes 

 Protorosaurus, Palaeohatteria, 

 Kadaliosaurus, distinctively 

 ambulatory and in part leap- 

 ing re])tiles, certainly carniv- 

 orous ; tlistinguished by the 

 straight limbs, strong develop- 

 ment of the hind limbs, corre- 

 lated with a dorsally expanded 

 ilium and from two to three 

 sacral vertebrae. 



These animals show all the 

 characters which we should 

 expect to find in the ancestors 

 ot carnivorous Dinosauria ; 



the 



too far specialized in the 

 direction of ambulatory and 

 predator)' tyi)es to have given 



any of the other known 



