Purple sea urchin  (Strongylocentrotus purpuratus)

Close up of purple sea urchin

© Jeff Rotman / naturepl.com

Purple sea urchin

© John Mason / www.ardea.com

Underside and mouth of purple sea urchin

© Jeff Rotman / naturepl.com

Purple sea urchin, spine detail

© D. R. Schrichte / SeaPics.com

Purple sea urchins on rocks

© John Mason / www.ardea.com

Purple sea urchins on rock

© Ken Lucas / www.ardea.com

Purple sea urchins grazing on kelp

© Jeff Rotman / naturepl.com

Purple sea urchins

© Georgette Douwma / naturepl.com

Purple sea urchin attacked by sea star

© Phillip Colla / SeaPics.com

Purple sea urchin predated by California sheephead

© Mark Conlin / SeaPics.com