PLATE XCI. 



c- — Rostrata. 

 Leptodksma Biton. 



I'age C22. 

 Fig. 1. An imperfect left valve of this species. 



Cliemmig- group. i>^imth nfjSmettqjo-H, Pa. 



LePTODESMA ALIFORME. 



P:ige -'-il). 

 See Plate 22. 

 Fiff. -. A la rye right valve ^showing; the pallial line awl muscular impression. This figure is given in 

 correction of fig. 28 of plate 22. 



Chemung grouj). Avyelha, N. Y. 



Leptodesma kujje. 



P;ise-221. 

 See Plate 2."). 

 Fiij. 'A. The left \alve described. This figure is given in correction of tig'ure 12, plate 2;"). 

 Chemung group. Ntar Sinethport, Pa. 



Leptoijesma Jason. 



Page 213. 

 Fio-. 4. \ left valve of the medium size. 



Chemung group. Canton. Bradford Co., Pa. 

 Fig'. ."). A I'ight valve somewhat imperfect, but pi'eserving the form of the body and cardinal expansions. 



Chemung group. Near Mansfield, Pa. 

 Fig. 8. A smaller rig-lit valve associated with the preceding- ' 



Leptodesma Lesleyi. 



Page 223. 

 Fig. 7. A large left valve showing the foi-m and sui-face markings. 

 , ' Chemung group. Susquehanna Co., Pa. 



Leptodesma aviforme. 



Page 2-24. 

 Fig. 8. An imperfect left valve. 



Chemung group. Tioga Co., Pa. 



d — Patulata. 

 Leptode.sjia flaccidum. 



Page 2-25. 

 Fig. 0. A left valve showing the charactei-istic form of the species. 

 Chemung- group. Laiorenceville, Tioga Co., Pa. 



Leptodesma patulum. 



Page 226. 

 Fig. 10. An imperfect left valve. 



Chemung group. Mansfield, Pa. 

 Fig. II. A right valve. 



Chemung group. Ma'mfield, Pa.", 



e — Arcoidea. 

 Leptodesma aecifoeme. 



Page -229. 

 Fig. 12. A large left valve. 



Chemung group. Mansfield, Pa. 



