Gastropods

Gastropoda (Greek, gastro, "stomach"; poda, "foot") is the largest class of molluscs, comprising more than 35,000 species of snails and slugs. It is the most successful molluscan class, having invaded a wide variety of habitats. The marine species (subclasses Prosobranchia and Opisthobranchia) are most commonly found in benthic habitats, but some species are pelagic. The third subclass, Pulmonata, has conquered land by eliminating the gills and converting the mantle cavity into a lung.