PLATE LXXXVIII. 

 Leiopteria Conradi. 



Page l.v.i 

 See Plate 20. 

 Fig-. 1. A left valve showing strong concentric undulations. 



Hamilton group. Leonardsville, Madison Co., X Y. 

 Fig. 2. A small left valve. 



Hamilton group. Canaiidaigwi Ink,. A r . Y. 

 Fig. 3. A large left valve imperfect on the anterior side. Tins figure is given in correction of fig. I. plate 20. 

 Fig. 4. An imperfect right valve. 



Hamilton group. Skaneateles lake, N. Y 



Leiopteria Dekayi. 



Page lb*. 



See Plates 19 and 20. 

 Fig. 5. The internal mould of a specimen preserving both valves, and showing the vertical plat 

 anterior to the beaks. 



Hamilton group. Pultonham, Schoharit Co., N. Y 

 Fig. 6. A large left valve with the wing partially restored. 



Hamilton group. ScTivJiarir Co.. N. Y. 

 Fig. 7. An enlargement of the surface on the umbonal slope of the specimen Kg 10. 

 Fig. 8. A left valve, preserving the striated ligamental area. 

 Fig. 9. A cardinal view of a portion of both valves showing the deep sulci anterior to the beaks. 



Hamilton group. Fttltonliain, Schoharie '<>.. N. Y. 

 Fig. 10. A small left valve showing the tine concentric stria' of the test. 



Hamilton group. Delphi. Onondaga Co., N. Y. 



Leiopteria Torre yi. 



Page 174. 



See Plate 22. 

 Fig. 11. A left valve of this species. 



Chemung group. Panama, Chautauqua Co., N. Y 



Leiopteria Troosti. 



Page 167. 

 Fig. 12. A left valve showing the form and surface characters. 

 Fig. 13. A portion of the surface enlarged to three diameters. 

 Hamilton group. Schoharie Co., N. Y. 



Leiopteria Gabbi. 



Page 169 

 Fig. 14. A left valve showing the form and surface character: 

 Hamilton group. Cayuga lake, N. Y. 



