No. 4] IDENTITY OF COTYLASPIS. 1 85 



is a sexually mature form and not a stage in the life cycle of 

 A. conchicola or of any other species ; that on these grounds 

 Leidy's designation is entitled to recognition ; that Platyaspis 

 atiodontae Osborn is a synonym of Cotylaspis msignis ; and 

 that Monticelli's genus Platyaspis should not be reduced to 

 a synonym of Cotylaspis from data at present available. 



Illinois State Laboratory of Natural History, 



University of Illinois, Urbana, Illinois. 



November 10, i8q8. 



