Littorinimorpha is a large order of snails, gastropods, consisting primarily of sea snails, but also including some freshwater snails and land snails.
Hydrobiidae, commonly known as mud snails, is a large cosmopolitan family of very small freshwater and brackish water snails with an operculum; they are in the order Littorinimorpha.
Bythinella is a genus of very small freshwater snails, an aquatic gastropod mollusk in the family Bythinellidae.
Bythiospeum is a genus of very small freshwater snails that have an operculum, aquatic gastropod mollusks in the family Moitessieriidae.
Moitessieria is a genus of minute freshwater snails with an operculum, aquatic gastropod molluscs or micromolluscs in the family Moitessieriidae.
Moitessieria simoniana is a species of minute freshwater snail with an operculum, an aquatic gastropod mollusc or micromollusc in the family Moitessieriidae. This species is found in France and Spain.
Palacanthilhiopsis is a genus of very small or minute freshwater snails with an operculum, aquatic gastropod mollusks in the family Moitessieriidae.
Paladilhia is a genus of minute freshwater snails with an operculum, aquatic gastropod molluscs or micromolluscs in the family Moitessieriidae.
Pseudamnicola is a genus of small brackish water snails with an operculum, aquatic gastropod mollusks in the subfamily Pseudamnicolinae of the family Hydrobiidae.
Lithoglyphidae is a family of small freshwater snails with gills and an operculum, aquatic gastropod mollusks.
Mercuria is a genus of small brackish water snails or freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
Iglica is a genus of very small freshwater snails with an operculum, aquatic gastropod molluscs in the family Moitessieriidae.
Islamia is a genus of small freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
Truncatelloidea is a superfamily of snails, gastropod mollusks in the clade Caenogastropoda.
Azecidae is a family of small and very small air-breathing land snails, terrestrial gastropod mollusks in the superfamily Azecoidea.
Spiralix is a genus of very small aquatic snails, operculate gastropod mollusks in the family Moitessieriidae.
