PLATE XXIII—Continued. 
Ptyciiopteria SINUOSA. 
Page 130. 
; See Plate 85. 
Fig. 13. A left valve showing the form and surface characters. The wing should be limited by a shallow 
furrow. 
Chemung group. Near Smetliport, Pa. 
Leptodesma Mentor. 
Page 205. 
See Plate 90. 
Fig. 15. An imperfect right valve supposed to belong to this species from its association. 
Chemung group. Near Smethport, Pa. 
Ptyciiopteria Sao. 
Page 132. 
See Plate 85. * 
Fig. 16. A left valve of medium size. The fold and furrow of the wing should be represented as stronger. 
Fig. 23. An associated right valve. 
Chemung group. Panama, Chautauqua Co., N. Y. 
Ptyciiopteria Salamanca. 
Page 131. 
Figs. 17, 18. Two left valves showing the form of the shell and surface characters. 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 beaks. ; , 
Fig. 20. The right side of a specimen preserving both valves partly opened. ; 
Chemung group. Near Sala'inanca, N. Y. 
Ptychopteria alata. 
Page 139. , 
See Plate 85. 
Figs. 21, 22. Two small right valves. 
Figs. 25, 26. Two larger characteristic right valves. 
Chemung group. Salamanca, N: Y. 
Ptychopteria Eucrate. 
Page 133. 
- See Plate 85. . 
Fig. 24. The right side of a specimen preserving both valves. 
Chemung group. Panavia, N. Y. 
Ectenodesma birostratum. 
Page 242. 1 : 
See Plate 84. 
Fig. 27. A right valve referred to this species, showing the form, surface ornamentation and strong, oblique 
lateral tooth. 
Chemung group. Pour miles north of Chenango Forks, N. Y. 
Figs. 28-30. Three left valves in different degrees of preservation, showing some variation in form and 
surface markings. , 
Chemung- group. Franklin, Delaware Co., N. Y. 
