Gastropods 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
Cepaea nemoralis: a European pulmonate land snail, which has been introduced to many other countries
The shell of Zonitoides nitidus, a small land snail, has dextral coiling, which is typical (but not universal) of gastropod shells.
The shell of Physella acuta, a freshwater snail, which is left-coiling (sinistral).