Gastropoda
The gastropods comprise about three-quarters of all known molluscs. They may be divided into three subclasses:
- Prosobranchia (gill-breathing). Almost all are marine. Usually a shell and an operuculum are present. Includes limpets, winkles and whelks.
- Opisthobranchia. Most species are marine. Reduction and loss of shell are common. Many are secondarily bilaterally symetrical. Includes the bubble-shells, sea-butterflies (pteropods) and sea-slugs.
- Pulmonata (lung-breathing). Shell usually present but operculum absent. Very nearly all the land and freshwater species of molluscs belong to this subclass.
Superfamilies with images
Other Superfamilies