Fig. 153. Diadema saxatile L. Part of the buccal membrane. 



Fig. 154. Centrostephanus coronatus Ai,. Ag.. the same. 



Fig. 155. Aspidodindema Anfillarum Al. Ag The whole buccal membrane. 



Fig. 156. Echinus escnlenhis L. Part of the buccal membrane. 



Fig. 157. Echinometra Mathosi Blv. The same. 



Fig. 158. Lytechimts semituberculatus Val. The same. 



Fig. 159. Echinocidaris nigra. Mol. The same. 



Fig. 160. Salenia Pattersoni. Al. Ag. The same. 



Fig. 161. Asthenos-oma variuni. Grube. Part of the ventral region. The 



lighter lines denote the overlapped portions of the plates. 



Fig. Kö. The pore of the 3" from the lip. 



Fig. 163. A the pore of the 8" plate detached into the buccal membrane, 



with the next, B, still fixed 



Fig. 164. The same of the 24'" plate. 



Fig. 165. The pore of tlie entire plate in V b, the 92' from the lip. 



Fig. 166. The same of the demi-plate 93. 



