Plate I. 



Fig. i. Spatangus altus L,tk. Type-specimen, actinal side. I / l . 



2. abactinal side. I / I . 



3. side view. I I I . 



4 



4. Raschi, the abactinal side. J /i. 



5. - actinal I II- 



- 6. Brisaster (Schizaster) fragilis, abactinal side. (Specimen from the Ingolf-St 35.) I ! I . 



7. abactinal side. (Specimen from Bergen.) I I I . 



