Plate 48. 



1-9. Arbacia punctulata Gray. 



1. Valve of tridentate pedicellaria. x 70. 



2. Valve of large tridentate pedicellaria. x 70. 



3. Valve of small tridentate pedicellaria. X 70. 



4. Valve of triphyllous pedicellaria. X 70. 



5. Valve of ophicephalous pedicellaria. x 70. 



6. Another valve of another ophicephalous pedicellaria. x 70. 



7. Disk-plate of pedicel, x 70. 



8. Supporting-plate of disk of pedicel. X 70. 



9. Calcareous rods from pedicels, x 70. 



10-14. Arbacia lixula Loven. 



10. Valve of tridentate pedicellaria. X 70. 



11. Valve of smaller tridentate pedicellaria. x 70. 



12. Valve of very small tridentate pedicellaria. x 70. 



13. Valve of triphyllous pedicellaria. X 70. 



14. Valve of ophicephalous pedicellaria. x 70. 



15-19. Arbacia spatuligera A. Ag. 



15. Valve of tridentate pedicellaria. x 70. 



16. Valve of triphyllous pedicellaria. x 70. 



17. Calcareous rods from pedicels, x 70. 



18. Upper end of stalks of pedicellariue. x 70. 



19. Spliaeridium. x 70. 



20, 21. Arbacia stellata Gray. 



20. Valve of triphyllous pedicellaria. x 70. 



21. Calcareous plates from pedicels. X 70. 



