David Fleetham / Sea urchin crab (Echinoecus pentagonus), female inside Common banded urchin (Echinothrix calamaris) rectum. Hawaii.

David Fleetham / Female Sea urchin crab (Echinoecus pentagonus) living in the rectum of the Common banded urchin, (Echinothrix calamaris), Hawaii, Pacific Ocean.

David Fleetham / A female Sea urchin crab (Echinoecus pentagonus) on the underside of a Panamic starfish (Pentaceraster cumingi), Hawaii.