WHydrobiidae, 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.
WAlzoniella is a genus of minute freshwater spring snails, aquatic gastropod mollusks or micromollusks in the family Hydrobiidae.
WAlzoniella slovenica is a species of very small or minute freshwater snail with an operculum, an aquatic gastropod mollusk in the family Hydrobiidae, which are sometimes known as the snouted water snails.
WAmnicola limosus, common name the mud amnicola, is a species of very small aquatic snail, an operculate gastropod mollusk in the family Hydrobiidae.
WBelgrandiella is a genus of minute freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
WBelgrandiella parreyssi is a species of minute freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae. This species is endemic to Austria where it is found only in one thermal spring at Bad Voeslau, south of Vienna. Due to man made changes of the habitat the population has been decreasing rapidly since the 1970s.
WBelgrandiella wawrai is a species of minute freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae. This species is endemic to Austria.
WEcrobia truncata, common name the truncated marsh hydrobia or minute hydrobia, is a species of very small aquatic snail, an operculate gastropod mollusk in the family Hydrobiidae.
WGraecoanatolica is a genus of small freshwater snails, aquatic gastropod mollusks in the family Hydrobiidae.
WGraecoanatolica macedonica is an extinct species of small freshwater snail, an aquatic gastropod mollusk in the family Hydrobiidae.
WGraziana is a genus of minute freshwater snails with an operculum, aquatic gastropod molluscs or micromolluscs in the family Hydrobiidae.
WHauffenia is a genus of minute freshwater snails with an operculum, aquatic gastropod molluscs or micromolluscs in the family Hydrobiidae.
WHauffenia sp. nov. is an as yet undescribed species of freshwater snail that lives underground, an aquatic gastropod mollusk in the family Hydrobiidae. This species is found in Slovakia.
WHydrobia is a genus of very small brackish water snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
WHydrobia acuta is a species of very small (4-6mm.) brackish water snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.
WIslamia is a genus of small freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
WLittoridinops is a genus of very small aquatic snails, operculate gastropod mollusks in the family Hydrobiidae.
WLittoridinops monroensis is a species of very small aquatic snail, an operculate gastropod mollusk in the family Hydrobiidae.
WMarstonia is a genus of freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
WMarstonia comalensis is a species of minute freshwater snail with a gill and an operculum, an aquatic gastropod mollusk or micromollusk in the family Hydrobiidae. It is found in south central Texas, United States.
WMarstonia scalariformis, previously known as Pyrgulopsis scalariformis, common name the moss pyrg, is a species of freshwater snail with a gill and an operculum, aquatic gastropod mollusk in the family Hydrobiidae.
WMercuria is a genus of small brackish water snails or freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
WMercuria similis is a species of small freshwater snail with an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.
WMexithauma quadripaludium is a species of freshwater snail, an aquatic gastropod mollusk in the family Hydrobiidae.
WNavalis is a genus of minute freshwater snails with an operculum, aquatic gastropod molluscs or micromolluscs in the Hydrobiidae family.
WThe New Zealand mud snail is a species of very small freshwater snail with a gill and an operculum. This aquatic gastropod mollusk is in the family Tateidae.
WOhridohauffenia is a genus of very small freshwater snails with an operculum, aquatic gastropod mollusks in the family Hydrobiidae, the river snails.
WPeringia is a genus of very small snails with gills and an operculum, gastropod mollusks in the family Hydrobiidae.
WPeringia ulvae, common name the Laver spire shell or mudsnail, is a European species of very small aquatic snail with gills and an operculum, a gastropod mollusk in the family Hydrobiidae.
WPseudamnicola is a genus of small brackish water snails with an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
WPyrgophorus is a genus of very small freshwater snails with a gill and an operculum, aquatic gastropod molluscs in the family Hydrobiidae.
WPyrgophorus coronatus is a species of very small aquatic snail, an operculate gastropod mollusk or micromollusk in the family Hydrobiidae.
WPyrgophorus spinosus, common name the spiny crownsnail, is a species of very small freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.
WPyrgula is a genus of freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.
WPyrgula annulata is a species of freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae.
WPyrgulopsis is a genus of freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
WNymphophilus minckleyi is a species of very small freshwater snail, an aquatic gastropod mollusk in the family Hydrobiidae.
WRifia is a species of very small freshwater snail with an operculum, an aquatic operculate gastropod mollusks in the family Hydrobiidae.
WSadleriana is a genus of small freshwater snails, aquatic gastropod mollusks in the family Hydrobiidae.
WSadleriana fluminensis is a land snail from the family Hydrobiidae.
WTanousia is an extinct genus of freshwater snails with gills and an operculum, a gastropod mollusk in the family Lithoglyphidae.
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