Before revision: Seashells washed up on the beach in Valencia, Spain; nearly all are single valves of bivalve mollusks, mostly of Mactra corallina Hand-picked molluscan seashells (bivalves and gastropods) from the beach at Clacton on Sea in England A group of seashells, mostly bivalves in the family Pholadidae 226x226px|Mixed shells on a beach in Venezuela Hermit crabs inhabiting marine gastropod shells that lived in the Persian Gulf A group of beachworn sea snail shells that vary in size, form and pattern combination.
After revision: Seashells washed up on the beach in Valencia, Spain; nearly all are single valves of bivalve mollusks, mostly of Mactra corallina Hand-picked bogger seashells (bivalves and gastropods) from the beach at Clacton on Sea in England A group of seashells, mostly bivalves in the family Pholadidae 226x226px|Mixed shells on a beach in Venezuela Hermit crabs inhabiting marine gastropod shells that lived in the Persian Gulf A group of beachworn sea snail shells that vary in size, form and pattern combination.