178 PAPERS, ETC. 



EXPLANATION OF PLATE II. 



Fig. 

 1. Theciäeum ornatum, Moore. Esterior of perfect shell en- 



larged. 

 2. . Interior of ventral valve, sliowing 



raisecl oval processes and septum. 



3. . Interior of small valve, mucli enlarged, 



sliOM-ing the serrated sej)tum and 

 tlie delicate loop for tlie support 

 of tlie brancliial membrane. 



4. Thecideum pygmaum, Moore. Perfect shell miicli enlarged. 

 5. . Interior of ventral valve. 



6. . Interior of dorsal valve, ditto. 



7. — . Profile of perfect shell. 



8. Crania canalis, Moore. Exterior of upi^er valve somewliat 

 enlarged. 



9. . Yoiing shell before possessing spinöse 



espansions. 



10. . Enlarged restoration of interior of valve, 



showing the musciilar impressions, and 

 the grooved form of the s^jines. 

 11. Crania Sandersii, liloove. Exterior of shell. 



12. . Interior of valve, giving the position 



and form of the ninscular impres- 

 sions. 



13. Crania Fonsoriii f?J, Eng. Deslongchamps. Exterior of 

 valve. 



14. . Interior of ditto. 



15. Discina Bundriensis, Moore. Enlarged exterior of shell. 



16. orhicularis, Moore. Exterior of valve enlarged. 



1 7. . Interior of ditto. 



1 8. . Block, with specimens of natiu'al size. 



19. Spirifera minima, Moore. Perfect enlarged exterior. 



20. . Exterior of the ventral valve. 



21. TerehratuJa (?) minuta, Moore. Perfect shell, enlarged 



exterior. 



22. . Interior of dorsal valve. 



23. Ehijnclionella f?y coronata, Moore. Enlarged dorsal aspect. 



24. . Interior, sho-n'ing ventral aspect. 



25. . Exterior of ventral valve. 



