PLATE XXII. 



Leptodesma ? sp. iudet. 



Fig-. 1. An obscure rijjht valve of an indeterminate character. 

 Chemung' group. Ithaca, N. T. 



Leptodesma complanatum. 



Page 327. 

 Fig-. •!. The left valve described. The strijE should turn backward along- the hinge posterioi- to the beak. 

 Chemung group. Philipsburg, Allegliany, Co., N. Y. 



Leptodesma Becki. 



Page 185. 

 Fig. 3. A large right valve. 



Chemung group. Co')iiing, Chemunc) Co., N. Y. 

 Fig. 4. A smaller imperfect example. 



Chemung group. Near PartrrUle, Cattaraugus Co., iV". 1'. 

 Fig-, "i. A small left valve showing the form and pi-oportions of the shell. 



Chemung group. Corning, iV. Y. 



Leiopteeia Torrevi. 



Page 174. 

 See Plate 88. 

 Figs. (i. 7. Two left valves, fig. 7, showing the characters of the species. 



Chemung group. Fig. 6, from Panama; fig. 7, from SakDnanm. N. Y. 



Leptodesma Matheri. 



Page 193. 

 See Plate 89. 

 Fig. 8. An imperfect left \alve of medium size. 

 Fig. 9. A I'ight valve. 



Fig. 10. A small left valve. The body of the valve is represented as too broad. 

 Chemung group. Bradford. McKean Co., Pa. 



Leptodesma potens. 



Page 188. 



See Plates 31 and 89. 

 Fig. 11. A right valve. 



Chemung group. Napoli, Cattaraugus Co., N. Y. 

 Fig. 12. A similar left valve. The extremity of the wing should be represented as acute as in fig. 19. 



Chemung gi-oup. Near Clean, N. Y. 

 Fig. 19. A large left valve. 



Chemung group. PortvUle. Cattaraugits Co., N. Y. 

 Fig. 20. A more elongate form referred to this species with some doubt. 



Chemung group. Randolph, Cattaraugus Co., N. Y. 

 Fig. 21. A large elongate left valve. 



Chemung group. Near Cassadaga. Chmitauqua Co.. N. Y. 



Leptodesma umbonatum. 



Page 198. 

 See Plate 90. 

 Fig. IB. The left valve described. Another figure of this specimen is given on plate 90, fig. 9. 

 Chemung group. Twenty Mile creek, Chautauqua Co., N. Y. 



