EXPLANATION OF THE PLATES. 



PLATE I. 



Fig. 



1. Phytolithus verrucosus. 



u. suppressed tubercles. 



c. longitudinal sulcus. 



2. Fhytolithus verrucosus. 



b. traces of leaves. 



d. included,cylindricalbody 



3. Fossil strobilus. 



a. tubular processes passing 

 from the internal part 

 to. the surface. 



4. Phytolithus caucellatus, epi- 



dermal surface. 



Fig. 

 5. 



6. 



7. 

 8. 



Phytolithus cancellatus, cortical 



surface. 

 Phytolithus cancellatus, ligneous 



surface. 



Transverse section of siphonia. 

 Upper extremity of siphonia, 



Websteri. 



PLATE II. 



Fig. Fig. 



1 . represents the general form and 6. 



characters of the genus echi- 7. 



nus and cidaris ; the tuber- 8. 



cles being perforated in the 9. 



latter genius. 10. 



2. Clypeaster. 11. 



3. Galerites. 12. 



4. ) r .. , . 13. 

 E > I'lbularia. 



Clypeus. 

 Cassidulus. 

 Kchinarachnius. 

 Ananchytes, the upper surface. 

 Scutella. 



Spatangus (Cor. Marinum). 

 Ananchytes, the under surface. 

 Spatangus (Ovum Marinum, 

 lirissus) . 



Fig. 



1. Planospirites. 



2. Oscana. 



3. Testacella. 



4. Patella. 



5. Fissurella. 



6. Emarginula. 



7. Concholepas. 



8. Stomatia. 



9. Argonauts. 



PLATE III. 



Fig. 



10. Carinaria. 



11. Sigaretus. 



12. Haliotis. 



13. Calyptrea. 



14. Infundibulum. 



15. Crepidula. 



16. Dentalium. 



17. Siliquaria. 



18. Vermicularia. 



Fig. 



19. Serpula. 



20 Pup'a. 



21. Aspergillum. 



22. Conus. 



23. Cypraea. 



24. Ovula, 



25. Bulla. 



26. Terebellum. 



