4 A REVISION OF THE COTYLOSAURIA OF NORTH AMERICA 



In October 1889 Cope presented in the "American Naturalist" (33) a "Synopsis 

 of the Families of the Vertebrata," in which the Cotylosauria is again mentioned as a 

 suborder of the Theromorpha with the families Pareiasauridce, Pariotichidce, and 

 Diadectidce. He defined the Cotylosauria as follows: "Ribs single-headed; tempo- 

 ral fossa overroofed; dentition abundant." In this paper Cope considered that he 

 corrected the original erroneous definition of the Cotylosauria based on the loss of 

 the basioccipital bone and placed it upon a firm basis. 



In the portion of Zittel's "Handbuch der Paleontologie" which appeared the 

 same year (69) the Cotylosauria is not reckoned as distinct, but the families Pario- 

 tichidce and Diadectidce are placed in the suborder Theriodontia (Pelycosauria Cope) 

 of the order Theromorpha. 



Lydekker in his "Catalogue of the Fossil Reptilia and Amphibia" in the British 

 Museum, 1890 (49), places the member of Cope's Cotylosauria in the Theromorous 

 Branch, Order Anomodontia, Suborder Theriodontia with the families Bolosauridce 

 and Diadectidce. 



In 1891 (34) Cope gave the following arrangement: 



Order Theromora. 



Suborder Placodontia. 



Family Placodontidce. 

 Suborder Proganosaurta. 



Families Mesosauridce, Procolophomdce, Proterosauridce, 

 Rhyncosauridce. 

 Suborder Anomodonta. 



Families Dicynodontidce, perhaps Endothiodontidce. 

 Suborder Theriodontia. 



Families Clepsydropidce, Pariotichidce, Bolosauridce. 

 Suborder Cotylosauria. 



Families Pareiasauridce, Bolosauridce. 



In 1892 Cope again raised the group to ordinal rank (35): 



Order Cotylosauria. 



Genera Pantylus, Chilonyx, Pariotichus. 

 Branch Theromora. 



Order Theriodontia. 

 Order Anomodontia. 



In this paper Cotylosauria was considered as the ancestral group of all reptiles. 

 In the same year Seeley (59) placed the group as a suborder of the order 

 Theriodontia with the Gennetotheria and "probably Pelycosauria." 

 In 1894 (36) Cope gave the classification below: 



Order Cotylosauria {Pareiasauria). 

 Order Theromora. 



Suborder Placodontia. 



Procolophonia. 



Anomodontia. 

 Order Pelycosauria {^Theriodontia). 



In the same year (37), in a discussion of Seeley' s papers, the order Cotylosauria 

 is defended by Cope against Seeley's Pareiasauria. He says: "Seeley founded the 

 Pareiasauria because the definition of Cotylosauria was defective in one respect. 

 This was remedied in 1889" (3i). 



