One of the classes of Mollusca, of great extent. It includes most of the marine spiral shells, and the land and fresh-water snails. They generally creep by means of a flat, muscular disk, or foot, on the ventral side of the body. The head usually bears one or two pairs of tentacles. See Mollusca.

Class of terrestrial and aquatic mollusks with one or two pairs of fleshy tentacles. Most gastropods have shells and a large foot however, both land and sea slugs have lost their shells in evolution. Most gastropods feed on algae or plant material, although a few groups are predatory. In the Chesapeake Bay, gastropods are represented by periwinkles, whelks, and nudibranchs (sea slugs).

a class of the phylum Mollusca that includes snails, sea slugs, nudibranchs, limpets, and cone shells. There are approximately 30,000 living species described. Many species are inhabitants of coral reefs and nearby seagrass beds