no THE AMERICAN NATURALIST. [Vol. XXXVIII. 



These forms also are too specialized to give rise to any of the 

 higher Diapsida; they represent an isolated and dying out 

 group. 



4. Order Gnathodontia Owen. 

 Rhynchosauria Osborn. 



the 



typified by R h y n c h o- 

 saurus, at the same time 

 that he proposed the 

 " family " Dicynodontia. 

 It seems proper that this 

 term should be given pri- 

 ority over the order Rhyn- 

 chosauria proposed b y 

 Osborn in 1903. 



Here again we have a 

 highly specialized division 

 resembling the Procolo- 

 phonia in general body 

 and cranial form, but dif- 

 fering from these animals 

 widely in the concentration 

 of pavement-like teeth on 

 the pterygopalatines and 

 the development of a large 

 edentulous bony beak. 

 They were probably lit- 

 toral, shell-eating animals 

 far removed from the true 

 Rhynchocephalia. 



lathodon 



1859, 



5. Order Pfi.vcosauri A Cope, 

 nd group, dexeloped in the Permian of Texas and 

 IS distinctively ambulatory and carnivorous. It is 

 zed by the abbreviation of the tail, the enormous 

 ■nt of the spines of the dorsal vertebrje, also by the 



