S12 EXPLANATION OF THE PLATES. 



Fig. 9. Siliceous specimen of Spongus Townsendi, p. 164. 



Fig. 10. Fossil coral, supposed to belong to the genus Millepora ; from the chalk marl, 

 p. 106. 



Fig. 11. Spongia ramosa, p. 162. 



TABLET XVI. 



Fig. 1. A Belemnite from the chalk at Brighton, p. 201. 



Figs. 2. 4. Madrepora centralis, p. ISO- 

 Figs. 3. 12. Entrochites ; or portions of the column of Apiocrinites elUpticus, p. 182. 



Fig. 5. Hamites armatus, p. 121. 



Fig. 6. Marsupites Milleri, shewing the pectoral plates in situ, p. 183. 



Fig. 7. The semilunar depression on the upper margin of the scapula in M. Milleri. 



Fig. 8. The outer surface of the clavicle of M. Milleri. 



Fig. 9. Clavicle and humerus of M. Milleri. 



Fig. 10. Octaedral sulphui-et of iron, from the Upper chalk, near Lewes, p. 155. 



Fig. 11. A group of crystals of sulphuret of iron, frcm the Lower chalk, near Lewes, 

 p. 140. 



Figs. 13, 14. Detached plates of Marsupites Milleri, p. 185. 



Fig. 15. Marsupites Milleri, p. 184. 



Fig. 16. Singular form of sulphuret of iron, from the chalk at Steyning, p. 153. 



Fig. 17, 18. Siliceous specimens of a Zoophyte of a pyriform shape, the nature of which 

 is unknown, p. 162. 



Fig. 19- Choanites Konigii, p. 179. 



Fig. 20. Vertical section of the same. 



Fig. 21. Transverse section of the same. 



Figs. 22, 23, 24. Different views of a species of Lunulites? p. 180. 



TABLET XVII. 



Fig. 1. A species of Cidaris, allied to C. saxatilis; from the grey chalk marl, p. 107. 



Fig. 2. Siliceous cast of Cidaris corollaris, p. 180. 



Fig. 3. Cerithium melanoides, from the Plastic clay, p. 263. 



Fig. 4. funatum, p. Wo. 



Figs. 5, 6. Detached specimens of the univalves contained in the Sussex marble ; and 

 described by Mr. Sowerby under the name of \i\y^axa,Jluvionim, p. 67. 

 Fig. 7. A polished slab of Sussex marble, p. 64. 

 Fig. 8. Conulus albogalerus, p. 190. 

 Fig. 9- Spatangus planus, p. 192. 



Fig. 10. rostratus, p. 192. 



Figs. 11. 14. Echinital spines, belonging to Cidaris claviger, p. 194. 



