Helmet Urchins Helmet urchins (Colobocentrotus atratus) on the rocks at Keahole Point Related Posts Vana Swirl Rough-Spined Urchin Postcard from the Reef - Banded Urchin Postcard from the Reef - The Horn of Urchin Death Share this:TweetWhatsAppEmail Author: Andrew An electrical engineer, amateur astronomer, and diver, living and working on the island of Hawaiʻi. View all posts by Andrew