PLATE 24. 



Page 

 Figs. 1-9. PrODUCTELLA RARI8PINA 170 



1. The ventral valve of a young individual. 



2, 8, 4. Three views of an adult individual, showing an irregular fold on the ventral vajve. 

 6. A ventral valve, preserving two of the spines and tlio bases of several otlicrs. 



6. A ventral valve, which is unusually symmetrical, and retains the marks of very few spines. 



7. A cardinal view of a ventral valve. 



8. The interior of a dorsal valve. 



9. Profile of specimen fig. 8. 



Figs. 10-16. Productella boydii 16'.» 



10. The ventral valve of a young individual. 



11. 12. The interior of dorsal valves, showing pustules from the indentations of the exterior. 

 13 - 15. Ventral valves of this species, preserving some of the spines. 



16. A profile view of the specimen fig. 16. 



Fig. 17-29. Productella hirsuta IGti 



17. The ventral valve of a young individual. 



18. 19. Ventral valves of large individuals. 



20. An impression of a dorsal valve. 



21, 22. Ventral valves preserving some of the submarginal spines. 



23. A profile of the specimen fig. 22. 



24. A .symmetrical ventral valve with short hinge line. 



25. A profile view of the proceding. 



26. A large and somewhat distorted ventral valve preserving some of the submarginal spines. 



27. The interior of a dorsal valve with cardinal process. 



28. An enlargement of the cardinal jjrocess from fig. 27. 



29. An enlargement of a portion of the surface, from a well preserved specimen. 



Figs. 30-37. Pboddctella hirsuta var. reotispina 1(58 



30. The dorsal valve of a small individual. 



31. A convex ventral valve. 

 82. A large ventral valve. 



33. An impicssion of the exterior of a large dorsal valve. 

 84. A large and somewhat distorted ventral valve. 

 35. A profile view of the same. 



86. The interior of a large ventral valve from which the shell has been mostly removed, pre- 



serving the submarginal spines. 



87. The interior of a dorsal valve from an impression in the stone. 



