Plate 4. 



1-12. Dorocidaris calacantha A. Ag. and Clark. 



1. Valve of small globiferou.s pediccllaria. x ~tr>. 



2. Valve of another small globiferous pedicellaria. x 5o 



3. Valve of tridentate pedicellaria. x 55. 



4. Ambital primary spine. Nat. size. 



5. Tip of same spine seen from side, x 5. 



6. End view of same tip. x 5. 



7. Abactinal primary spine. Nat. size. 



8. Actinal primary spine, x 11. 



9. Interambulaeral secondary spine, x 11. 



10. Ambulacra! secondary spine, x 11. 



11. Actinostomal miliaries. x 11. 



12. Other miliaries. x 11. 



13-19. Chondrocidaris gigantea A. Ag. 



13. Small globiferous pedicellaria. x 23. 



14. Tridentate pedicellaria. x 23. 



15. Valve of sraall globiferous pedicellaria. x 156. 



16. Exterior view of same valve, x 156. 



17. Valve of tridentate pedicellaria. x 55. 



18. Interior view of base of valve of tridentate pedicellaria. x .55. 



19. Side view of tip of valve of tridentate pedicellaria. x 15(). 



20-23. Stephanocidaris hawaiiensis A. Ag. and Clark. 



20. Valve of small globiferous pedicellaria. x 156. 



21. Tip of valve of small globiferous pedicellaria. x 156. 



22. Valve of tridentate pedicellaria. x 55. 



23. Interior view of base of valve of tridentate pedicellaria. x 55. 



