Plate VI. 



Fig. i. Stereocidaris ingolfiana, from above, '/i- 

 2. - the side. I / I . 



3. Test of Stereocidaris ingolfiana. I / I . 



4. Apical area of 2 /i- 



5. Ambulacral-processes of Stereocidaris ingolfiana. I / I . 



6. - Doroctdaris papillata. I / I . 



7. Interambulacral area - I / s . 



8. Piece of ambulacral area of Dorocidaris papillata. ^ 



9. Cidaris af finis. */!. 

 10. Interambulacral area of Cidaris af finis. 2 /,. 



ii. Piece of ambulacral area of Stereocidaris ingolfiana. 

 _ 12. - - Porocidaris piwptirata. 4 



