PLATE L. 
PAL2EONEILO emarginata. 
Page 338. 
Figs. 1-6. A series of right valves showing the gradations in size and the prevailing characters of the 
species. 
Hamilton group. Onondaga, Cayuga and Schoharie Co's, N. Y. 
Figs. 7-10. A series of left valves. 
Hamilton group. 
Fig. 11. A right valve of a small individual enlarged to two diameters. 
Lower Chemung group. Ithaca, N. Y. 
Paiaeoneilo BISULCATA. 
Page 344. 
Figs. 12-14. A right and two left valves enlarged to two diameters. 
Chemung group. Near Elmira, N. Y. 
Pal^eoxeilo PERPLANA. 
Page 339. 
See Plate 93. 
Figs. 15-18. A series of left valves, showing gradation in size and variation in form. 
Fig. 19. An enlargement of the left valve of an individual with the umbo cut away, showing the crenulated 
hinge. 
Hamilton group. Ludlowville, N. Y. 
Fig. 20. A specimen retaining the two valves in conjunction. 
Hamilton group. Bear's gulf, Schoharie Co., N. Y. 
Fig. 21. A large right valve. 
Hamilton group. Bear's gulf, Schoharie Co., N. Y. 
Fig. 22. A specimen retaining both valves in conjunction. 
Hamilton group. Bear's gulf, Schoharie Co., N. Y. 
PAL2EON EILO ARATA. 
Page 341. 
Fig. 23. The right side of a specimen retaining the two valves in conjunction. 
Hamilton group. Near Norwich, Chenango Co., N. Y 
P a E/EOXEILO brevis. 
Page 342. 
Figs. 24-30. Natural casts of the interior of right and left valves, presenting the general form of the fossils 
and showing the anterior muscular scar. 
Chemung group. Franklin, Delaware Co., N. Y. Fig. 30 from Philipsburgh, N. Y. 
Fig. 31. A specimen preserving the surface markings. 
Chemung group. Philipsburgh, N. Y. 
Fig. 32. A small specimen preserving the surface markings and showing the crenulations of the hinge. 
Chemung group. Philipsburgh, N. Y. 
Fig. 33. A cast of a right valve showing muscular scars. 
Chemung group. Franklin, Delaware Co., N. Y. 
