Fig. 1. 
Fig. 2. 
Fig. 8. 
Fig. 9. 
Fig. 11. 
Fig. 3. 
Figs. 7,: 
Fig. 12. 
Fig. 4. 
Fig. 13. 
Fig. 14 
Figs.[5, 
PLATE XVI. 
Pterinea consimilis. 
Page 100. 
See Plate 84. 
A small right valve, showing the strong radii on the wing and their absence over the body. 
A larger right valve, imperfect at the posterior margin. 
An imperfect left valve, showing a very broad striated ligamental area. 
Chemung group. Near Elmira, N- Y. 
A similar left valve of somewhat shorter form. 
Chemung group. Near Elmira, N. Y. 
A 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 group. Near Elmira, N. Y. 
Pterinea Chemungensis. 
Page 98. 
See Plate 84. 
A right valve, showing the form and surface ornamentation. 
Chemung group. Chemung river. Upper Narrows, N Y. 
10. Two left valves of very erect form. 
Chemung group. Chemung Narrows, N. Y. 
A left valve, more oblique than the preceding. 
Chemung group. Chemung river, Uppei ■ Narrows, N. Y. 
Pterinea prora. 
Page 102. 
An imperfect right valve. The specimen shows the pallial line and muscular scar. 
Chemung group. Near Elmira, N. Y. 
The right side of a specimen preserving a part of. the right valve lying in the impression of 
the left one. 
Chemung group. Near Elmira, N. Y. 
An impression of a right valve, retaining a portion of the left valve around the pallial margins. 
Pterinea rigida. 
Page 101. 
6. Two left valves, showing the characteristic form and ornamentation of the species. 
Chemung group. Chemung Co., N. Yr 
