Land snails and slugs are members of the class Gastropoda, meaning “stomach-foot,” because they move upon a large, muscular ventral surface called a foot. Gastropods include both land and aquatic snails, and are members of the phylum Mollusca, a diverse array of invertebrate animals including clams, mussels, limpets, chitons, tusk shells, octopuses and squid. Land snails are special in that they evolved from aquatic ancestors and possess many unique adaptations to survive in terrestrial habitats.
Many species of land snails are very tiny; in fact most North American species are the size of a lentil or smaller. Some species are the size of a pin head.