Plate 45. 

 1-6. Colobocentrotua Stimpaoni A. Ag. 



1. The disk of an actinal pedicel. 



2. The basal part of one of its laminje. 



3. Part of a typical spicule. 



4. A deformed spicule. 



5. Fragment of a deformed spicule. 



6-10. Colobocentrotua Mertenaii Brandt. 



6. Fragment of a spicule. 



7. Basal part of a lamina. 



8. Shows the quadratic arrangement of the spicules. 



9. Typically formed spicule. 



10. Top of a pedicel, taken from the abactinal side and hidden by the large radicles. 



Figures 1-5 are from a specimen, 88 mm. in diameter including the spines and those 

 of 6-10 from an individual, measuring 70 mm. in diameter. 



Bonin Ids., Captains Ringgold and Eodgers, N. P. Ex. Ex., Dr. Wm. Stimpson Coll. 



