PLATE LXXXIII. 



Pterinopecten regularis. 



Page 7(i. 

 Fig. 1. A left valve showing- the characteristic form and sni-fare markiufifs. 

 Hamilton g-roup. TAiiing.itim Co., N. Y. 



Pterinopecten Vehtumnus. 



i'age 71. 

 8ee Plate 5. 

 Fig. 2. A small specimen preserving- the left valve entire and a portion of the right -s'alve. 



Hamilton group. Onondaga Co., N. Y. 

 Fig. 3. A left \-alve to show the characters of the surface ornamentation. 

 Hamilton group. Sknneatdes lake, N. Y. 



Pteuinopecten intermedius. 



Page 68. 

 See Plate 17. 

 Fig. -4. A left valve wholly denuded of the test. 



Hamilton gi-oup. Cayiiga lake, N. Y. 

 Fig. 5. A left valve as obtained from an imjn'ession of the extei-ior in the matrix, showing- the foi-m anil 

 surface markings. 



Hamilton group. Cayuga lake, N. Y. 



