Plate I. 



Fig. I. Spatangus altus Ltk. Type-speciraen, actinal side. '/i- 



— 2. — — — abactinal side. "/i- 



— 3. — — — side view. '/i. 



— 4. — Raschi\ the abactinal side. Vj. 



— 5. — — - actinal — Vj. 



— 6. Brisaster (Schizasfer) fragilis, abactinal side. (Specimen from the « Ingolf »-S t. 35.) ^'j. 



— 7. — — — abactinal side. (Specimen from Bergen.) '/,. 



