Plate 5. 



1-17. Phyllacanthus Thomasii A. Ag. and Clark. 



1. Small globiferous pedicellaria. x 23. 



2. Tridentate pedicellaria. x 23. 



3. Valve of small globiferous pedicellaria. x 156. 



4. Small valve, from side, x 156. 



5. Valve of tridentate pedicellaria. x 55. 



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



7. Ambital primary spine. Nat. size. 



8. Tip of same spine, x 5. 



9. End view of same tip. x 5. 



10. Actinal primary spine. Nat. size. 



11. Primary spine nearest actinostome. Nat. size. 

 12, 13. Interambulacral secondary spines, x 11. 



14. Ambulacral secondary spine, x 11. 



15. Actinal secondary spine, x 11. 



16. Side view of same spine, x 11. 



17. Miliariea x 11. 



18-20. Stereocidaris grandis IXul. 



18. Valve of globiferous pedicellaria. x 55. 



19. Valve of small globiferous pedicellaria. x oo. 



20. Valve of tridentate pedicellaria. x 55. 



