Diadema antillarum

…setosum of the Indo-Pacific, and D. antillarum of Florida and the West Indies, have toxic spines up to 30 centimetres (12 inches) long. The slate-pencil urchin (Heterocentrotus mammillatus) of the Indo-Pacific has 12-cm spines that may be 1 cm thick—stout enough to be used for writing. Lytechinus variegatus, a pale-greenish…