PLATE LXXXIX. 



a — Spinifera. 



Leptodesma spinigerum. 



Page 177. 

 See Plate 21 . 

 Fig. 1. A li'ft valve preserving' the siiiiiifiuMii extension of the cardinal ani^U^. 

 Chemung- g-roup. Clionnnrj river, ahoxv Ehidra, N. Y. 



Leptodesma longispinum. 



Page 179. 

 See Plate 21. 

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



Fig. 4. A large imperfect right valve preserving a p<n'tion of the finely striated ligamental area. 

 Chemung group. Near Elmlra. N. Y. 



Leptodesma Shumardi. 



Page isn. 

 Pigs. 5, 6. Two left valves varying somewhat in foi-m and proportions. 

 Chemung group. Niar EJmirn, lY. Y. 



Leitodesma potens. 



Page 188. • 



See Plates 21 and 22. 



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



Chemung gi'ouji. Near Oknn, N. Y. 



Leptodesma kobu.stum. 



Page 181. 



See Plate 21. 

 Fig. 8. A large left \-alve. 



Chemung group, t>teiihen Co., N Y. 



