396 



NEW YORK STATE MUSEUM 



Lunulicardium? (Opisthocoelus ?) transversale sp. nov. 



Page 246 



16 A left (?) valve showing the undistorted form and the surface 

 characters. X5 

 Naples subprovince Ithaca 



Genus pterochaenia gen. nov. 



Page 247 



Pterocliaenia fragilis Hall (sp.) var. orbicularis var. nov. 



[See pi. 5] 

 Page 252 



17, 18 Right and left valves of large shells. X3 



Ithaca province Near Noblesville, Otsego co. 



Pterochaenia perissa sp. nov. 



Page 253 



19 A right valve with the extraordinary byssal flange. X3 



Naples subprovince Parrish gully, Naples 



Pterochaenia cashaquae sp. nov. 



Page 254 



20. 21 Right valves. X3 



22 A left valve. X5 



23 A right valve. X5 



24 A right valve. X3 



25 A left valve. X5 



Genesee valley Cashaqua creek 



Pterochaenia elmensis sp. nov. 



Page 254 



26, 27 Right and left valves. X3 



Chautauqua subprovince 



Big Buffalo creek, East Elma, Erie co. 



