PLATE XVII. 



ACTINOPTERIA MURICATA. 



Page 1C8. 



Fig. 1. A small left valve sliowinsf the extent of the wing-, X 2. The .surface of the wing .should show 



several fine radii. 

 Fig. 2. A larger left valve, X 2. The extremity of the wing is not sufficiently extended in the figure, and 



the surface has fine radii which ai'e not represented. 

 Fig. 3. A left valve preserving- the mucronate extensions of the radii along the ventral margin, X 2. 

 Marcelhis shale. Littleville, Livingston Co., N. Y. 



ACTINOPTERIA DOEIS. 



Va.ee 109. 

 Fig. 4. A left valve of this species, enlarged to two diameters. 

 Marcelhis shale. East Bloomfield, N. Y. 



LeIOPTERIA LvEVIS. 



Page 158. 

 See Plate 20. 



Figs. 5, (i. Two right valves, X 2. Fig. G is incoi-rectly restored on the ventral margin and the wing. 

 Figs. 7-11. Left valves showing the prevailing characters of the species, X 2. 

 Marcelhis shale. Livingston and .EHe counties, iV". Y. 



Leptodesma Marcellense. 



Page 175. 

 Fig 12. The left \-alve described, X 2. 



Marcellus shsde. Hast Bloomfield, N. Y. 



Pterinopecte.v Hermes. 



Page (14. 

 Fig. 13. A small left viilve. The extremity of the ear i.-* represented too acute and the pallial margin is 

 reflexed in the specimen. 



Hamilton group. Canandaigua lake, JV. Y. 

 Fig. 14. A larger left valve. 



Hamilton g-roui). Ontario Co , JV. Y. 

 Fig. 15. The interior of a left valve. 



Hamilton group. Caiimulaiyua lake, N. Y. 



