Platr 90. 

 1-4. Phrissocystis aculeata A. Ag. ; Station 3366. 



1. Fragment showing the odd posterior interambulacrum and adjoining plates. 



2. The left posterior ambulacrum and adjoining plates (fragment). 



3. Fragment showing the anal system with surrounding plates and part of the left 



posterior ambulacrum. 



4. Fragment showing part of the odd posterior interambulacrum and adjoining pUtes 



near the ambitus on the abactinal side. 



*l 



