Amber Penshell

Found buried in mud, sand, or recesses in the reef, with just the valves slightly exposed, over coral and rocky reefs. Often found encrusted with organisms, which may be for camouflage.

Most Bivalves are permanently anchored in fissures or depressions in the rock surface of the reef, some may become covered in algae and other marine life.
Other Bivalves swim free, either by a well developed foot or propelled along by a jet of water from their mantle cavity.