PLATE XX A . 



Page 

 Fi<*s. 1-10. Porcellanaster ciERULEUS, Wyville Thomson, . . 134 



Fig. 1. Abactinal aspect ; magnified 3 diameters. 



Fig. 2. Actinal aspect ; magnified 3 diameters. 



Fiff. 3. Profile view : magnified 3 diameters. 



Fio-. 4. A portion of the actinostome, showing the buccal membrane, and an 

 adjacent radial area ; magnified 5 diameters. 



Fig. 5. An actinal interradial area ; magnified 6 diameters. 



Fig. 6. A terminal plate, abactioal aspect ; magnified about 7 diameters. 



Fig. 7. Actinal aspect of the same ; magnified about 7 diameters. 



Fig. 8. A pair of ambulacral plates, seen in profile ; magnified 5 diameters. 



Fig. 9. Ambulacral plates seen from above ; magnified 5 diameters. 



Fig. 10. Lateral view of the same, showing the adambiilacral plates ; magnified 5 

 diameters. [The character of the latter is somewhat exaggerated.] 



[These figures appear to have been drawn from a dried or shrunken example. 



The plate was prepared under the direction of Sir Wyville Thomson, and I 

 was unfortunately not aware of its existence until the greater part of the text and 

 nearly all the plates had been printed off.] 



