EXPLANATION OF THE PLATES. SIS 



Fig. 12. Spines referable to Cidaris sceptrifera, p. l&i. 

 Fig. 13. Spine oi CiAa.ris papillata, p. 194. 

 Fig. 15. Conulus suhrotundus, p. 191. 



Fig. 16. albogalei'iis ; the acute variety, p. 190. 



Fig. 17. Front view of Spatangus rostratus. 

 Fig. 18. The base of Conulus suhrotundus. 



Fig. 19. albogalerus, var. acuta. 



Fig. 20. The base of fig. 8. 

 Fig. 21. The base of Spatangus ^fcnz/s. 



Figs. 22, 23. Different views of a species of Spatangus from Brighton; allied to S. 

 prunella, p. 193. 



TABLET XVIII. 



Figs. 1, 2, 4, 5, 6, 10. Views of various specimens of Rostellaria Parkinsoni, from the 

 chalk marl, p. 108. 



Fig. 3. Cast of Auricula simulata, p. 111. 



Fig. 7. Trochus agglutinans? p. 109. 



Fig. 8. Voluta amhigua, attached to a fragment of an Ammonite, p. 108. 



Fig. 9. Trochus, related to T. agglutinans, p. 109. 



Fig. 11. Cast of a species oi Ampullaria, p. 111. 



Fig. 12. Cirrus perspcctivus, p. 194. 



Fig. 13. Portion of an unknown species of Buccinum, p. 108. 



Figs. 14, 15. Vermicularia Soieerbii, p. 111. 



Fig. 16. A distorted specimen of Trochus linearis, p. 110. 



Fig. 17. Trochus linearis, p. 110. 



Figs. 18, 22. Different views of Cirrus depressus, p. 195. 



Figs. 19, 20. A species of HeUx, from the Plastic clay at Castle Hill, p. 263. 



Fig. 21. View of the base and umbilicus of Cirrus perspectivus. 



Fig. 23. A species of Teredo, p. 207. 



Fig. 24. Vermicularia umbonata, p. 111. 



TABLET XIX. 



The whole of the fossils represented in this plate, with the exception of figs. 1, 2, 3, and 

 34, are from the Blue chalk marl, near Lewes. 



Fig. 1. Cast of a species of Pecten or Plagiostoma, p. 129. 



Figs. 2, 3. Auricula incrassata, from the Grey chalk marl, p. 110. 



Fig. 4. Dentalium striatum, p. 87. 



Fig. 5. Cast oi^McxAa, pectinata, p. 94. 



Figs. 6, 9. Perfect specimens of Nucula pectinata. 



s s 



