PLATE LXXXV. 



PT YCIIO l'TE I! I A T 1 I ETI8. 

 Page 135. 

 Figs. 1-3. Three left valves showing 1 some variation in form and obliquity. 

 Fig. 4. A right valve referred to this species. 



Chemung group. Panama. N. V 



PTYCIK iPTERIA gibbosa. 

 Page 149. 

 Fig. 5. A left valve showing the large anterior end and short wing, with the broadly gibboue body < > i* 1 1 1 • - 

 valve. Chemung group. Warren, Pa. 



Ptychop tekia fai.cata. 



Tapre 136. 

 Fig. 6. An entire left valve, showing the form and surface markings. 

 Fig. 7. A smaller example of the same valve. 



Chemung group. Alleghany Springs, Warren Co., Pa. 



Ptychopteria SINUOSA. 



Page 130. 

 See Plate 23. 

 Fig. 8. A left valve showing the oblique cardinal and lateral teeth. 

 Chemung group. Warren, Pa. 



PTYCHI IPTERTA E0DORA. 

 Page 138. 

 Fig. 9. A left valve of this species showing its elongate form. 

 Chemung group. Panama, N. F. 



Ptychoptekia et,ongata. 



Page 141. 



Fig. 10. A cardinal view of a specimen preserving both valves. 



Fig. 11. The ventral view of a smaller specimen with the valves closed. 



Fig. 12. A large right valve of this species. 



Fig. 13. The left valve of the specimen tig. 10. 



Chemung group. Panama, N. Y. 



Ptychoptekia Sad. 

 Page isa. 

 See Plate 23. 

 Fig\ 14. A small left valve. 

 Fig. 15. The left valve of a larger example. 

 Fig. 16. A specimen of medium size. 

 Fig. 17. The cardinal view of a small individual, showing the prominent beak and umbo of the left valve 



as compared with the right. 

 Fig. IS. The ventral view of a specimen preserving both valves. 

 Chemung group. Panama, N. T. 



Ptychoptekia Spio. 



Page 137 

 Fig. 19. A left valve of this species. 



Chemung group. Panama, X. Y. 



Ptychopteria spatulata. 



Page 144. 

 Fig. 20. A left valve showing its large size and broad elongate form. 

 Chemung group. Warren, Pa. 



