PLATE LIV 



PAGE 



Figs. 1-6. DALMANELLA PLANICONVEXA (Hall) 298 



I, 2. Dorsal and ventral shells. X 1 1 A. Helderberg formation, New 



Scotland member, 21st Bridge. 



3. Ventral valve. Helderberg formation, Becraft member, Cherry Run, 



W. Va. 



4. The interior of dorsal valve of a smaller individual. 



5. Interior of ventral valve. 



6. Cardinal view of a larger individual. New Scotland formation, New 



York. 



Figs. 7-10. DALMANELLA CLARK i Maynard n. sp 300 



7. Interior of ventral valve. X 2 1 /&. 



8. Dorsal valve. X 2. 



9. Ventral valve. X 2. 



10. Interior of dorsal valve. X 2. 



Helderberg formation, Keyser member, Cash Valley. 



Figs. 11-13. DALMANELLA CONCINNA (Hall) 301 



II. Ventral valve. 



12. Surface ornamentation. X 7. 



13. Dorsal valve. 



Helderberg formation, Keyser member, Cumberland. 



Figs. 14-23. DALMANELLA PERELEGANS (Hall) 299 



14, 15. Ventral and dorsal valves. Helderberg formation, New Scot- 

 land member, Corriganville. 

 16-19. Ventral, dorsal, side, and cardinal views. 



20. Interior of ventral valve. 



21. Internal cast of ventral valve. 



22. Internal cast of dorsal valve. 



23. Interior of dorsal valve. 



New Scotland formation, New York. 



Figs. 24-26. DALMANELLA EMINENS (Hall) 299 



24. Dorsal view. 



25. Profile outline of same. 



26. Interior of ventral valve. 



Helderberg formation, New Scotland member, Corriganville. 



