Ok, so I know sea urchins are echinoderms, not molluscs, but its a related question.  Does anyone know of a book(s) that have ID's for sea urchin tests (shells)?  I know I've seen one, but unfortunately I forgot where and didn't think to write down any info on it (although I think it was a book on Hawaiian inverts, I seem to remember Heterocentrotus mammillatus being in there).  I have several urchin tests, and I know you can identify species by the patterns of nodules, grooves, etc on them.  Anybody know of a place I can look to help with that?  Thanks!

 

~Stephen~