PLATE XVI. 



PtEKIN'EA CONSIMILIS. 

 Page 100. 

 See Plate 84. 

 Fig-. 1. A small right valve, showing the strong- radii on the wing and their absence over the body. 

 Pig-. 2. A larger right valve, imperfect at the posterior margin. 

 Fig. 8. An imperfect left valve, showing a very broad striated Ugamental area. 



Chemung group. Ntar Elmira. iV. T. 

 Pig. 9. A similai- left valve of somewhat shorter form. 



Chemung group. JVear Elmira, N. Y. 

 Fig.' 11. k left valve, .showing some irregularity in the concentric markings of the shell along the ven- 

 tral margin ; probably due to a natural irregularity in the growth of the shell. 

 Chemung gi-oup. iVertr Elmira, K. Y. 



Pterinea Chemungensis. 



Page 98. 

 See Plate 84. 

 Pig. 3. .A right valve, showing the form an<i surface ornamentation. 



Chemung group. Chemung river. Upper Narrows, N. Y. 

 Pigs. 7, 10. Two left valves of very erect form. 



Chemung group. Chemung JVarrows, N. Y. 

 Fig. 12. A left valve, more oV)lique than the preceiling. 



Chemung group. Cliemung river. Upper Narrows, N. Y. 



PlERINEA PROEA. 

 Page 103. 

 Fig. 4. An imperfect right valve. The specimen shows the pallial line and muscular scar. 



Chemung group.  Near Elmira, N. Y. 

 Fig. 13. The right side of a specimen preserving a part of the right valve Ijing in the impression of 

 the left one. 



Chemung group. Near Elmira, N. Y. 

 Fig. 14. An inipre.s.sion of a right valve, retaining a portion of the left valve around the pallial margin.s. 



Pterinea rigida. 



Page 101. 

 Figs.JS, 6. Two left valves, showing the characteristic form and ornamentation of the si>ei"ies. 

 Chemung group. Chemung Co., N. Y.' 



