Cincinnati Society of Natural History. 



EXPLANATION OF PLATE VIII. 



AhL THE FIGURES ARE MAGNIFIED TWENTY DIAMETERS. 



Figs, i to 3. — Ctenobolbina subcrassa, n. sp., p. 180 



1. — A right valve. 



2 and 3. — Lateral and ventral views of a left valve. 



Stones River group, High Bridge, Ky. 



Fig. 4. — Ctenobolbina obliqua, n. sp., p. 180 



A right valve retaining some of the flange. 

 Trenton group, Kenyon, Minn. 



Fig. 5. — Ctenobolbina spiculosa, n. sp., p. 181 



Nearly perfect right valve. 



Hamilton group, Falls of the Ohio. 



Fig. 6. — Ctenobolbina armata, n. sp., p. 181 



A right valve showing the usual characters of the species. 

 Hamilton group, Falls of the Ohio. 



Figs. 7 to 9. — Ctenobolbina cavimarginata, n. sp., p. 182 



7 and 8. — Lateral and posterior views of a left valve. 

 9. — View of interior of another left valve. 

 Hamilton group, Falls of the Ohio. 



Figs. 10 and 11. — Ctenobolbina insolens, n. sp p. 182 



10. — Exterior of a left valve. 



11. — Interior of another left valve. 



Hamilton group, Falls of the Ohio. 



Fig. 12. — Ctenobolbina granosa, n. sp., p. 183 



A perfect left valve. 



Lower Helderberg group, Albany County, N. Y. 



Figs. 13 and 14. — Ctenobolbina loculata, n. sp., p. 184 



13. — Exterior of a right valve, apparently perfect. 



14. — Interior of a left valve. 



Kinderhook group, Mt. Pleasant, Tenn. 



Figs. 15 to 18. — Kirkbya cymbula, n. sp., p. 184 



15. — A right valve. 



16. — A left valve, relatively shorter. 

 17 and 18. — End and ventral views of same. 



Hamilton group, Falls of the Ohio. 



Figs. 19 to 22. — Kirkbya germana, n. sp., p. 185 



19. — A right valve. 



20. — End view of same. 



21. — A left valve, relatively longer. 



22. — Vertical edge of same. 



Hamilton group, Falls of the Ohio. 



