Plate XI. 



Fig. I. Piece of transverse sectioii of a primary spine of Cidaris affinis. Obj. II. Oc. o. 



— 2. — - — — - spines of Tromikosovia Koehleri; a — b. sections of primår)' actinal 



spines, c. of an abactinal spine. Obj. II. Oc. I. 



— 3. Piece of transverse section of a primary spine of Porocidaris purpiirata. Obj. II. Oc. I. 



— 4. — - — — - spines of Hygrosoma Petersii\ a. section of a primary actinal 



spine, b. of an abactinal spine. Obj. II. Oc. I. 



— 5. Piece of transverse section of spines of Calveria hystrtx; a. section of a primary actinal spine, 



b. of an abactinal spine. Obj. II. Oc. I. 



— 6. Transverse section of a primary spine of Hypsiechhtus coronatus. Obj. II. Oc. III. 



— 7. Piece of transverse section of ^ines of PJiorinosoma placenta ; a. section of an abactinal spine, 



b. of a primary actinal spine, lower part. Obj. II. Oc. I. 



— 8. Piece of transverse section of a primår}- spine of Aræosonia fenestratum. Obj. II. Oc. I. 



— g_ _ . — — - spines of Sperosoina Griinaldii\ a. section of a primary actinal 



spine, b. of an abactinal spine. Obj. II. Oc. I. 



— 10. Transverse section of a primary actinal spine of PJwniiosovia placenta, outer part. The out- 



line indicates the circumference of the bag of skin. Obj. II. Oc. I. 



— II. Spicule of a tnbe foot of Aræosoma tesselatum. Obj. II. Oc. III. 



— 12. a. b. Spicules from the organs of Stewart of Stereocidaris ingolfiana. Obj. II. Oc. I. 



— 13. Spicules of a tube foot of Trojnikosoina Koehleri. Obj. II. Oc. I. 



— 14. Piece of transverse section of a primary spine of Dorocidaris papillata, young specimen. 



Obj. II. Oc. o. 



— 15. Spicules of a tube foot of Aræosoma coriaceitm; a. from |the outer, b. from the lower part 



Obj. II. OcIII. 



— 16. a — d. Spicules of the genital organs of Stereocidaris ingolfiana. Obj. II. Oc. I. 



— 17. Piece of a primår}' spine of a young Stereocidaris ingolfiana. Obj. 00. Oc. o. 



— 18. Spicules of a tube foot, lower part, of Kainptosoma asterias {^Ph. tenue>\ Chall. St. 272). 



Obj. II. Oc. I. 



— 19. Spicules of a tube foot of Hapalosoma pellucidum. Obj. II. Oc. III. 



— 20. — — — - Asthenosoma variiun. Obj. II. Oc. III. 



— 21. — — — - Porocidaris pnrpurata. Obj. II. Oc. I. 



— 22. — — — - Cidaris affinis; a. from the outer, b — c. from the lower part. 



Obj. II. Oc. I. 



— 23. Piece of the intestine, with imbedded spicules, of Stereocidaris ingolfiana. Obj. II. Oc. I. 



— 24. — - transverse section of a primary spine of Dorocidaris (?) micans. Obj. II. Oc. I. 



— 25. Spicules of an abactinal tube foot of Phormosoma placenta. Obj. II. Oc. I. 



— 26. a — d. — of a tube foot of Dorocidaris papillata. Obj. II. Oc. III. 



— 27. — — — - Hygrosoma Petersii. Obj. II. Oc. I. 



— 28.a — d. — — — - Stereocidaris ingolfiana. Obj. II. OcIII. 



— 29. — — — - Calveria hystrix. Obj. II. Oc. III. 



— 30. Piece of a primary spine with the crest of a }'oung Stereocidaris ingolfiana. Obj. 00. Oc. o. 



— 31. — - transverse section of a primary spine of Dorocidaris papillata., larger specimen. 



Obj. II. Oco. 



— 32. Piece of the crest of a primary spine of Stereocidaris ingolfiana. Obj. II. Oc. o. 



— 33. — - transverse section of a primary spine of Stereocidaris ingolfiana. Obj. II. Oc. I. 



