PRATE LXXXIII—Continued. 
Pterinopecten exfoliatus. 
Page 61. 
See Plate 1. 
Fig. 6. A left valve as obtained from an impression of the matrix, showing the form and surface characters. 
Fig-. 7. A large imperfect left valve with the test almost wholly exfoliated and presenting a strong contrast 
with the preceding. 
Limestone of Marcellus shale. Genesee Co., N. Y. 
Crenipecten Leon. 
See Plate 9. 
Fig. 8. The left valve described showing the hinge characters and form of the valve. 
Chemung group. Leon, Cattaraugus Co., N. Y. 
Crenipecten liratus. 
Page 87. 
See Plate 9. 
Fig. 9. A left valve showing the form and size of the .ears given in correction of tig. 24, plate 9. 
Chemung group. Connewango, Cattaraugus Co., N. Y. 
Crenipecten impolitus. 
Page 83. 
See Plate 9. 
Fig. 10. A small left valve. 
Chemung group. Olean, N. Y. 
Pterinea flabella. 
1 Page 93. 
* See Plates 14 and 15. 
A large left valve showing but three strong radii. 
Chemung 1 group. Lawenceville, Tioga Co., Pa. 
The internal mould of a left valve, showing the ligamental area, lateral and cardinal teeth, pallial 
line and both muscular impressions. 
Hamilton group. Schoharie Co., N. Y. 
Pterinea pinguis. 
Page 92. 
See Plate 15. 
Fig. 13. A left valve showing the form and proportions; redrawn from the specimen of fig. 2, plate 15. 
Upper Helderberg group. Near Colu/mbus, Ohio. 
Pterinea grandis. 
Page 91. 
Fig. 14. A large left valve imperfect on the anterior end. 
Upper Helderberg group. Lexington, Scott Co., hid. 
Fig. 11. 
Fig. 12. 
