Pete Oxford / Galapagos green sea urchin (Lytechinus semituberculatus) Galapagos. Endemic.

Norbert Wu / Sea Urchin (Lytechinus variegatus) covered with coral, shells, and urchin skeleton to prevent predation, West Palm Beach, Florida

Norbert Wu / Sea Urchin (Lytechinus variegatus) covered with coral and shells to prevent predation, West Palm Beach, Florida

Pete Oxford / Galapagos Green Sea Urchin (Lytechinus semituberculatus) mass off of Fernandina Island, Galapagos Islands, Ecuador

Norbert Wu / White Sea Urchin (Lytechinus anamesus) group attack and feed on a larger Red Sea Urchin (Strongylocentrotus franciscanus), southern California

Tui De Roy / Two Chocolate chip seastars (Nidorellia armata) with Green sea urchin (Lytechinus variegatus) on sea floor, Galapagos Islands, Ecuador. Pacific Ocean.

Tui De Roy / Galapagos green sea urchin (Lytechinus semituberculatus) colony on rocky seabed, Fernandina Island, Galapagos, South America.

Tui De Roy / Chocolate chip sea star (Nidorellia armata) and Galapagos green sea urchin (Lytechinus semituberculatus) scattered across the seabed, Isabela Island, Galapagos, South America, Pacific Ocean.