PLATE XXIII— Continaotl. 



PtYCHOPTERIA SINIOSA. 



Page 130. 



See Plate 85. 



Fig. 13. A left valve showing the form and surface characters. The wing should be limited by a shallow 



furrnw. 



Chemung group. Near Smethport, Pa. 



Leptodesma Mentor. 



Page 20b. 

 See Plate 90. 

 Fig. 15. An imperfect right valve supposed to belong to this species from its association. 

 Chemung group. Near Sinethport, Pa. 



Ptyciioi'teria Sao. 



Page U-2. 

 See Plate 8.5. 

 Fig. 16. A left valve of medium size. The fold and furrow of the wing should !)<> n'liresented a.s stronger. 

 Fig. 23. An associated right valve. 



Cliemung gi-oup. Panama, Chautauqua Co., N. Y. 



Ptyctiopteria Salamanca. 



Page 131. 

 Figs. 17, 18. Two left valves showing the foi-m of the shell and surface character. Fig. 18 should show an 



alar fold similar to fig. 17. 

 Fig. 19. A cardinal view of the specimen, fig. 18, showing the relative convexity of the valves and the com- 

 parative elevation of the lieaks. 

 Fig. 20. The right side of a specimen preserving both valves partly opi'oed. 

 Chemung group. Near Salamanca, iV. Y. 



PtYCHOPTERIA ALATA. 



Page 13H. 



See Plate 85. 

 Figs. 21, 22. Two small right valves. 

 Figs. 25, 26. Two larger characteristic right valves. 



Chemung gi-oup. Salamanca, N. Y. 



PtYCHOPTERIA EuCRATE. 



Page 133. 



See Plate 85. 



Fig. 24. The right side of a specimen preserWng both valves. * 

 Chemung group. Panama, N. Y. 



ECTENODESMA BIROSTRATf.M. 



Page -242. 



See Plate 84. 



Fig. 27. A right vahe leferrod to this .species, showing the form, surfai-e oi-namentation and strong, oblique 



lateral tooth. 



Chemung grouji. Four miles north of Chenango Fork.i, N. Y. 

 Figs. 28-30. Three left valves in ditfi-rent degrees of preservation, showing some variation in ftirm and 

 surface marliings. 



Chemung group. Franklin, Ddaxeare Co.. N. Y. 



