Gastropoda
The Gastropoda or gastropods are a large taxonomic class within the molluscs, a group of animals that are more commonly known as snails and slugs. The class includes snails and slugs of all kinds and all sizes: huge numbers of marine snails and sea slugs, as well as freshwater snails and freshwater limpets, and the terrestrial (land) snails and slugs. The class Gastropoda contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes all the way back to the Late Cambrian.