PLATE XIV. 

 Pterinea flabella. 



l'age 93. 



See Plates 15 and 83. 



Fit:'. i. A left valve of a small sj imen of more than usual obliquity. 



Hamilton gi-oup. Eastern N. Y. 

 Pig. 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. 

 Kg. 3. A left valve of a well preserved specimen of medium size, showing the general form and char- 

 acters. Hamilton group. Eastern X. Y. 

 Fig. 4. A left \ :l1\ <■ somewhat narrower than the preceding. 



Hamilton group. Pratt's Falls. Onondaga Co., Hf. Y. 

 Big. :>. A left valve having a broad bodj and extended ■wing. 



Hamilton group. Tally, X. Y. 

 Kg. 6. A large imperfect specimen with an unusually 4arge wing. 



Hamilton group Madison Co., X. Y. 

 Fig. 7. An imperfect left valve of narrow, erect form, sh iwing the striated ligamentaJ area. 



Hamilton group. Skaneateles lake, X. Y. 

 Pig. 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 spscimens from the hard calcareous layers. 

 Hamilton group. Delphi, X. Y. 

 Pigs. 9 13. \ series of right vah es : figs. 10, 11 and I- being the reverse of tigs. J. s and 5, respectively. 

 Pig. 14. A profile view of the specimen figs. 8 and LI, showing the comparative depth of the valves. 

 Pig 15. The internal mould of a right valve, showing the anterior and posterior muscular impressions, 

 the pallia! line with the cardinal and lateral teeth. 



Hamilton gi p. Pratt's fulls, Oimuiliiga Co.. X. Y. 



Fig. lti. The interior from a gutta-percha mould, showing the term of the teeth and the muscular scars. 

 Figs. 17. Is. The vertical and cardinal views of a natural internal mould of a fragment of a left valve 

 showing the characters of the interior. 



Hamilton group. Otsego Co., X. Y. 



19. The interior. as obtained fr a gutta-percha impression. 



Pig. 20. The internal mould of a small left valve preserving the hinge characters and muscular scars. 

 Hamilton group. Otsego Co., N. Y. 



Pig. 21. Tie- ii r surface of the cardinal portion of a left valve showing the ligamentaJ area. 



Hamilton group, Pratt's Falls, Onondaga Co., X. Y. 



