Gastropods

thumb|Helix pomatia sealed in its shell with a [[calcareous epiphragm]]

Gastropods (; previously known as Univalves; class Gastropoda ) are a vast and diverse group of invertebrates within the phylum Mollusca, comprising the animals commonly known as snails and slugs. With an estimated 65,000 to 80,000 living species, they form the second-largest animal class after the insects. The fossil record of gastropods extends back to the Late Cambrian. , 721 families are recognized—476 extant (some with fossil representatives) and 245 extinct known only from fossils.

thumb|right|This female specimen of the queen conch, Aliger gigas, shows signs of imposex: it has developed a male sexual organ (verge) due to previous exposure to [[organotin compounds.]] Imposex is a disorder observed in certain marine and freshwater gastropod mollusks, where female individuals develop male sexual characteristics, such as a penis and vas deferens, due to exposure to specific environmental pollutants. This condition is primarily induced by organotin compounds, notably tributyltin (TBT), which have been widely used in antifouling paints for ships to prevent biofouling. Unlike

mollusc

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sinistral garden snail; Internet celebrity