PLATE I. 



I FA«E. 



LiNGL'LA OOVINGTONENSIS , 67 



Fig. 1. View of the exterior of the ventral (?) valre, as obtained by a gutta-peroha cast from the 

 matrix. Enlarged to 2 diameters. 



LiNGULELLA ClNCINNATIENSIS , 67 



Fig. 2. View of the dorsal side of a specimen, imperfect in the lower part, showing the beak and area 

 J of the ventral valve. 

 3. View of a shell, somewhat restored, to show the general form as seen in other individuals. 



Trematis jiillepunctata 70 



Fig. 4. Dorsal side of a specimen from CincinDati, Ohio, showing the general form of the shell and 

 some of the external piTDctaj around the margiu. 



5. Ventral side of the same specimen, showing the slit in the posterior margin. 



6. Profile of the same, showing the relative proportion of the valves and curvature of the beak. 



7. Interior of a ventral valve, apparently of the same species. All the figures are enlarged. 



Trematis punctostriata 70 



Fig. 8. View of a ventral valve from the soft shales at Cincinnati, showing the punctate strife over 

 a part of the surface. 

 9. Ventral valve from the same locality. From the cabinet of U. P. James, Esq. 



Leptobolus lepis - 69 



Fig. 10. Interior of a dorsal valve, greatly enlarged, showing muscular inpressions, etc. 



11. Interior of a ventral valve, showing muscular impressions and cardinal area. Enlarged. 

 The specimens were from the cabinet of C. B. Dyer, Esq. 



SCHIZOCEANIA FILOSA 73 



Fig, 19. View of a shell of Stropho-mena altemata, to which thore are five individuals of this species 

 adhering, three of which show remains of the npper valve, and all of them more or less of 

 the lower or attached valve. Natural size. 



13. Enlarged view of an upper valve, one of a group of three individuals attached to S. alternata. 



14. Enlargement of an-upper valve, from which the shell has been removed, showing the mus- 



cular impressions. The specimen ia attached to a valve of Strophomena altemata. 



15. Enlargement from the ventral valv^, seen near the right side of fig. 12, showing the thicken- 



ing of the margins of the notch. 



Crania l^lia 75 



Fig. 16. View of the inner valve of StreptorhyTtchus planumbona, H., with foui' specimens of this 

 species attached. • 



Crania scaeiosa , 74 



Fig. 17. View of a specimen of JStrophonuna alteimata, from Cincinnati, Ohio, with a group of these 

 shells adheiing. 



Orthis clytie 75 



Fig. 18. View of the interior of a ventral valve. 



19. View of the exterior or dorsal side of an entire shell. These figures are from the original 

 specimens of the species. 



Orthis ella ; , 76 



Fig. 20. Dorsal view of one of the original specimens of the species. (See Pal. Ohio, Vol. I., p. 105.) 



Orthis Jamesi 77 



Fig. 21. View of the dorsal side of the largest of the type specimens of this species. 

 22. Profile view of the same. 



Tellinomya levata , , 82 



Fig. 23. View of the hinge of an imperfect specimen of this species. ' Enlarged. 



Telunomya pbctunculoides 81 



Fig. 24. View of the interior of a specimen from the cabinet of C. B. Dyer, Esq. Enlarged. 



LyEODESMA ClNCINNATIENSIS 82 



Fig. 25. Enlarged view of the interior of a right valve, showing the character ot the hinffe. Cabinet 

 of C. B. Dyer, Esq. * 



