Any member of the class Gastropoda, the largest group of
Gastropods, which include the snails , conchs , whelks , limpets , periwinkles , abalones , slugs , and sea slugs (see nudibranch ), are found worldwide, in marine, freshwater, and terrestrial environments. Gastropods typically have a large foot with a flat sole for crawling, a single coiled shell that covers the soft body, and a head that bears a pair of eyes and tentacles. However, they are so diverse that some forms lack shells, while animals in one genus have shells with two halves, like {{link=bivalve">bivalves . Most feed by using a radula, a ribbon of small horny teeth that tear food into pieces. They may be herbivores, carnivores, predators, parasites, or filter feeders of plankton and detritus.