Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
PLATE XCI. 
c — Rostrata. 
Leptodesma Biton. 
Page 222. 
1. An imperfect left valve of this species. 
Chemung group. South of Smethport, Pa. 
Leptodesma aliforme. 
Page 220. 
See Plate 22. 
2. A large fig ht valve 'showing the pallial line and muscular impression. This figure is given in 
correction of fig. 28 of plate 22. 
Chemung group. Angelica, N. Y. 
Leptodesma rude. 
Page 221. 
See Plate 25. 
8. The left valve described. This figure is g-iven in correction of figure 12, plate 25. 
Chemung group. Near Smethport, Pa. 
Leptodesma Jason. 
Page 213. 
4. A left valve of the medium size. 
Chemung group. Canton, Bradford Co., Pa. 
5. A right valve somewhat imperfect, but preserving the form of the body and cardinal expansions. 
Chemung group. Near Mansfield, Pa. 
6. A smaller right valve associated with the preceding- j 
Leptodesma Lesleyi. 
Page 223. 
7. A large left valve showing the form and surface marking's. 
Chemung group. Susquehanna Co., Pa. 
8. An imperfect left valve. 
Chemung group. 
Leptodesma aviforme. 
Page 224. 
Tioga Co., Pa. 
d — Patulata. 
Leptodesma flaccidum. 
Page 225. 
9. A left valve showing the characteristic form of the species. 
Chemung group. Lawrenceville, Tioga Co., Pa. 
Leptodesma patulum. 
Page 226. 
10. An imperfect left valve. 
Chemung group. Mansfield, Pa. 
11. A right valve. 
Chemung group. Mansfield, Pa.” 
12. A large left valve. 
Chemung group. 
e — Arcoidea. 
Leptodesma arciforme. 
Page 229. 
Mansfield, Pa. 
