NAPLES FAUNA IN WESTERN NEW YORK, PART 2 407 



Genus exjthydesma Hall 



Page 291 



Euthydesma subtextile Hall 



Page 292 



8 A left valve showing oblique corrugations and postumbonal 



ribs 



9 The posterior portion of the ligament area from a squeeze. X2 



10 A left valve with fine concentric and radial striae 



1 1 A cast of the outside of the central part of the ligament area 



showing the striation and the median fold on the hinge. X2 



12 The same viewed from above or the cavity of the beak. X2 



13 A small right valve with cancelating surface markings 



14 A large right valve 



Chautauqua subprovince Correll's point, Lake Erie 



15 A small valve showing a cicatrix or fold running obliquely 



forward from the beak with growth lines concentric to it 

 Chautauqua subprovince Forestville 



16 A small suberect shell 



17 A young shell with fine umbonal ribs 



Chautauqua subprovince Correll's point, Lake Erie 



