PLATE P. 



■ Phyllacanthus imperialis, /. 1-6. 



1. Large abactinal interambulacral spme, fluted at tip. 



1". Small abactinal interiuubulacral spine, fluted and banded. 



2. Magnified end view of Fig. 1. 



3. Large abactinal interambulacral spine, fluted at tip and banded. 



4. Small actinal interambulacral spine. 



5. 6. Magnified profile and tip of Fig. 3. 



Phyllacanthus dubia, f. 7 - 10. 



7. Long, smooth, abactinal interambulacral spine, slightly fluted at tip. 



8. Short aliactinal interambulacral spine, fluted half-way from tip. 



9. Short, smooth, pointed interambulacnil abactinal sjiine, very slightly fluted at tip. 



10. Short, stout, abactinal interambulacral spine, fluted its whole length. 



Phyllacanthus baculosa, /. 11 - 20". 



11, 12. Large abactinal interambulacral spines, in-egularly serrated. 



13. Long, pointed abactinal interamliulaeral spine, strongly serrated and fluted at tip. 

 13". Magnified base of Fig. 13. 



14, 15. Magnified tip of Fig. 13, in profile, and end \dew. 



16. Short abactinal interambulacral pointed serrated .spine. 

 16°. Magnified base of Fig. 16. 



17. Short abactinal interambulacral smooth spine. 



18. Shorter interambulacral flattened serrated spine, near ambitus. 



19. Shorter, serrated at edges only, granular interambulacral actinal spine. 



20. Short, sharp, pointed abactinal interambulacral thorny spine. 

 20«. Magnified base of Fig. 20. 



Phyllacanthus annulifera, /. 21 - 26". 



21. Large abactinal interambulacral spine, spiny and serrated, banded. 



22. Small, smooth abactinal interambulacral spine, banded. 



23. Short, stout, cupped actinal interambulacral spine. 



25. Short, slender, cupped actinal interambulacral spine. 



26. Small, slender, serrated interambulacral abactinal spine. 

 Se". Magnified base of Fig. 26. 



Phyllacanthus gigantea, /. 27' - 31. 



27. Long, spiny abactinal interambulacral spine. 



28. Shorter abactinal interambulacral spine, with lamellar serration. 



29. Short abactinal interambulacral spiny spine. 



30. 31. Short actinal interambulacral spines. 



