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.
Bithynia is a genus of small freshwater snails with an operculum, aquatic prosobranch gastropod mollusks in the family Bithyniidae.
Gyraulus is a genus of small, mostly air-breathing, freshwater snails, aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails.
Bythinella is a genus of very small freshwater snails, an aquatic gastropod mollusk in the family Bythinellidae.
Moitessieria is a genus of minute freshwater snails with an operculum, aquatic gastropod molluscs or micromolluscs in the family Moitessieriidae.
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.
Plagigeyeria is a genus of very small or minute freshwater snails with an operculum, aquatic gastropod mollusks 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.
Theodoxus is a genus of nerites, small water snails with an operculum, some of which live in freshwater, and some in both freshwater and brackish water, aquatic gastropod mollusks in the family Neritidae, the nerites.
Valvata is a genus of very small freshwater snails with an operculum, aquatic gastropod mollusks in the family Valvatidae, the valve snails.
Vitrea is a genus of small, air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Pristilomatidae.
Moitessieriidae is a family of small freshwater snails, aquatic gastropod molluscs in the superfamily Truncatelloidea.
Islamia is a genus of small freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
Spiralix is a genus of very small aquatic snails, operculate gastropod mollusks in the family Moitessieriidae.
