mollusks crepidula (gastropoda) attached to the shell of a horseshoe crab

slipper limpet gastropod snail mollusca mollusc calyptraeidae snails cup saucer molluscs seashells schnecke amerikanische pantoffelschnecke crepidula gastropoda horseshoe crab limulus polyphemus beach atlantic shell ocean sand nature coast animal wildlife coastline water shore crustacean brown xiphosura fauna arthropods arthropoda invertebrate reptantia cancer shrimp ancient arthropod marine life shells