New Jersey Scuba Diving

These creatures are all of the order Gastropoda - having a single, often coiled, shell, as opposed to the bivalves, which have two matching shells. Most snails are hermaphroditic. Also, most snails have a right-hand twist to the shell, although there are exceptions.

Right:
X-ray image of a Channeled Whelk, showing internal structure.

Nudibranchs are a form of snail that has lost its shell, while Corollas and Sea Butterflies are snails that have abandoned not just their shells, but the snail-like existence entirely, swimming up into the water column as plankton.

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