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STUDIES IN EVOLUTION 



Pterygometopus Schmidt. 

 Ptychasjns Hall. 

 Ptychometopus Schmidt. 

 Ptychoparia Corda. 

 Ptychojyyge Angelin. 

 Raphiophoriis Angelin. 

 Remopleurides Portlock. 

 Salteria Walcott. 

 S alter ia W. Thompson. 

 Sao Barrande. 



Schmidtella Tschernyschew. 148 

 Schmidtia Marcou. 

 Selenopeltis Corda. 

 Shumardia Billings. 

 Solenopleura Angelin. 

 Sphcerexochus Bey rich. 

 Sphcerocoryphe Angelin. 

 SphcBropthalmus Angelin. 

 Staurocephalus Barrande. 



