8 



A REVISION OF THE COTYLOSAURIA OF NORTH AMERICA 



"B. Supratemporal roof narrow, orbit very large; skull smooth; lateral teeth expanded 

 transversely to the axis of the jaws. 



No lateral temporal vacuity 3. Teltrpetida 



A small lateral temporal foramen 4. Procolophonid<e" 



REPTILIA 

 THEROMORPHA 



MAMMALIA 



Anomodontia 



All other reptiles 

 (Reptilia Heteromorpha) 



Cotyloesuri* 



PareiasaturU 



Rhyncooephalia 



Labyrinthodontia 



Microsauria 



BATRACHIA STEGOCEPHALIA 



In 1904 Williston (64) raised objections to placing the Cotylosauria in Osborn's 

 subclass Dtapsida and asserted his belief that Cope was most nearly correct in his 

 scheme proposed in 1896 in the "Primary Factors of Organic Evolution," in which 

 the Cotylosauria are regarded as the most primitive reptiles. Following is Cope's 

 scheme as indorsed by Williston: 



Pteroaauria 



Mammals 



Dinosauria 



Sauropteryjia 



Crocodilia 



Rhyncooephalia 



Icthyoaauria 



\ 

 Cotylosauria 



Anomodontia 



