576 E. C. CASE 



2. The similarity of the Poliosauridae"^ and the Clepsydra pidae to 

 the reptiles from the known Permian of Europe and Africa. 



3. The similarity of certain amphibians, especially Eryops and 

 Trimerorhachis, to known Permian forms. 



4. The presence of Janassa, Ceratodus, Ctenodus, Diplodus, and 

 Strigilina. 



5. He suggests the similarity of Pariotichus of Texas and Pro- 

 colophon of South Africa. 



These points will be discussed seriatim. 



1. The argument from the presence of reptiles may be rejected 

 at once as this is part of the question on trial. In a later paper 

 {Proc. Am. Phil. Soc, 1897, p. 88) Cope identifies one of his Permian 

 reptiles from Illinois, Isodectes, in a form that he previously considered 

 as an amphibian, Tuditanus from the Coal Measures of Linton, 

 Ohio. So that he himself recognized the possibility of reptiles 

 occurring below the Permian. The validity of this identification 

 may be questioned, however. 



2. The morphological similarity between the reptiles from the 

 Illinois and Texas beds and reptiles from known Permian beds of 

 Europe and Africa. 



Cope depends on three points in particular. 



a) The resemblance between Clepsydrops and Lycosaurus from 

 the Permian of South Africa. This, with all other comparisons 

 between the reptiles of the two continents (except perhaps the Cotylo- 

 sauria) may be dismissed, as the forms have been shown to be so 

 radically different (Diapsidan in North America and Synapsidan in 

 South Africa) as to preclude any possibility of their use in indicating 

 the contemporaneity of the beds. 



h) The resemblance of Clepsydrops to Deuterosaurus of Russia. 

 The skulls of Deuterosaurus and Rhopalodon have repeatedly been 

 described, but their condition is such that no definite conclusions 

 can be drawn, but the weight of evidence seems to be that they are 

 nearer to the South African forms than to the North American. 



c) The notochordal condition of the vertebrae, and the resem- 

 blance of certain humeri to humeri from the Permian of France. 

 The first character cannot be considered as distinctive of the Permian; 



I Case, Publication 55, Carnegie Institution, Washington. 



