PLATE XIV. 
Pterinea flabella. 
Page 93. 
See Plates 15 and 83. 
Fig-. 1. A left valve of a small specimen of more than usual obliquity. 
Hamilton group. Eastern N. Y. 
Fig. 2. The left valve of another'specimen, given to show the appearance produced by having a portion 
of the margin and wing removed. 
Hamilton group. Eastern N. Y. 
Fig. 3. A left valve of a well preserved specimen of medium size, showing the general form and char¬ 
acters. Hamilton group. Eastern N. Y. 
Fig. 4. A left valve somewhat narrower than the preceding. 
Hamilton group. Pratt's Falls, Onondaga Co., N. Y. 
Fig. 5. A left valve having a broad body and extended wing. 
Hamilton group] Tally, N. Y. 
Fig. 6. A large imperfect specimen with an unusually large wing. 
Hamilton group. Madison Co., N. Y. 
Fig. 7. An imperfect left valve of narrow, erect form, showing the striated ligamental area. 
Hamilton group. ■ Skaneateles lake, N. Y. 
Fig. 8. The left side of a specimen from which the shell has been removed leaving only the marks of the 
stronger radii in the cast, a common condition of the specimens from the hard calcareous layers. 
Hamilton group. Delphi, N. Y. 
Figs. 9-13. A series of right valves ; figs. 10,11 and 12 being the reverse of figs. 2, 8 and 5, respectively. 
Fig. 14. A profile view of the specimen figs. 8 and 11, showing the comparative depth of the valves. 
Fig-. 15. The internal mould of a right valve, showing the anterior and posterior muscular impressions, 
the pallial line with the cardinal and lateral teeth. 
Hamilton group. Pratt’s falls, Onondaga Co., N. Y. 
Fig. 16. The interior from a gutta-percha mould, showing the form of the teeth and the muscular scars. 
Figs. 17, 18. The vertical and cardinal views of a natural internal mould of a fragment of a left valve 
showing the characters of the intex-ior. 
Hamilton gi-oup. Otsego Co., N. Y. 
Fig. 19. The intei-ioi-, as obtained from a gutta-pei-cha impression. 
Fig. 20. The internal mould of a small left valve preserving the hinge characters and muscular scars. 
Hamilton gi-oup. Otsego Co., N. Y. 
Fig. 21. The inner surface of the cai’dinal portion of a left valve showing the ligamental area. 
Hamilton gi-oup. Pratt’s Falls, Onondaga Co., N. Y. 
