PLATE LXI. 
GnUAMMYSrA ARCUATA. 
Page 373. 
See Plates 63, 93. 
Figs. 1-5. A series of valves presenting the usual characters of the species. 
Figs. 6, 7. Left side and anterior views of a specimen which is vertically compressed. 
Fig. 8. The right valve of a large individual. 
Hamilton group. Schoharie Co., N. Y. 
Fig. 9. Cardinal view of a specimen vertically compressed, giving an extreme angularity to the umbonal 
slope. 
Hamilton group. Shore of Canandaigua lake, N. Y. 
GrAMMYSIA SUBARC DATA. 
Page 375. 
See Plate 93. 
Figs. 10-12. A series of left valves of the usual character. 
Figs. 13-15. Larger individuals of the same species. 
Figs. 16, 17. The left side and cardinal view of a compressed specimen. 
Chemung group. Near Elmira, N. Y. 
Fig. 18. A cardinal view of a compressed specimen. 
Lower Chemung group. Ithaca, N. Y. 
Fig. 19. A cardinal view of a crushed specimen. 
Lower Chemung group. Ithaca, N. Y. 
Fig. 20. A cardinal view of a crushed specimen. 
Fig. 21. The right side of a vertically compressed specimen. 
Chemung g-roup. Near Elmira, N. Y. 
Fig. 22. An enlargement of the surface strife on the post-cardinal slope of the specimen tig. 19. 
Grammysia u n data . 
Page 379. 
See Plates 64, 93. 
Fig. 23. A small left valve. 
Chemung group. Near Panama, N. Y. 
