Any species of gastropod that glides along on a broad tapered foot and has a high coiled shell into which it can withdraw.
Snails are found in the ocean, in fresh waters, and on land. Most marine snails have gills in the mantle cavity (see mollusk ). Most land and freshwater snails have no gills; they use the mantle cavity itself as a lung. Snails may be either scavengers (of dead plant or animal matter) or predators. Some species are used as food, and the shells of some are used as ornaments. See also limpet , periwinkle , slug , whelk .