PLATE XX. 
Figs. 1-7. PoRcELLANASTER CHRULEUS, Wyville Thomson, . 2 
, Fig. 1. Abactinal aspect ; magnified 3 diameters. 
Fig. 2. Actinal aspect ; magnified 3 diameters. 
| Fig. 3. Profile view; magnified 3 diameters. cae 
Fig. 4. A cribriform organ; magnified 10 diameters. 
Fig. 5. A portion of the abactinal surface ; raieriee 20 diameters. 
Fig. 6. Abactinal aspect of a young example; magnified 3 diameters. 
7. Actinal aspect of a young example ; magnified 3 diameters. 
