PLATE LXXXIX. 



a — Spinifera. 



Lf.PTODESMA SP1NIGERTJM. 

 Page 177. 

 See Plate 21. 

 Fig. I. A left valve preserving the spiniform extension of the cardinal angle. 

 Chemung group. Chemung river, i dra, N. F. 



LePTODESMA LONGISl'IXUM. 

 Page 179 

 See Piatt- 21. 

 Figs. 2, 3. Two left valves varying slightly in form and surface markings. 



Fig. 4. A large imperfect right valve preserving a portion of the finelj striated ligamental area. 

 Chemung group. Near Elmira, N. T. 



Leptodesma Shtjmardi. 



Pago 180. 

 Figs. 5, 6. Two left valves varying somewhat in form ami proporti 

 Chemung group. Near Elmira, N. Y 



Lepiodesma potens. 



Page 188. • 



See Plates 21 and 22. 

 Fig. 7. A nearly entire right valve of this species. 



Chemung group. Near Olean, N. Y. 



Leptode>jia kobustum. 



Page 181 



See Plate 21. 

 Fig. 8. A large left valve. 



Chemung group. Steuben Co., .V Y. 



