Pulmonata or pulmonates is an informal group of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includes many land and freshwater families, and several marine families.
Pulmonata
Shells of pulmonate stylommatophoran snails in a museum collection
An artistic but scientifically incorrect version of various European land snails and slugs (one species here is not a pulmonate), their food plants and fungi, and a beetle that eats mollusks, bottom right.
Examples of Pulmonata: Achatina fulica top right, Bielzia coerulans top left, Praticolella berlandieriana center right, Megalobulimus oblongus in the center, Euglandina rosea center left, Helix pomatia bottom right & Ashmunella levettei bottom left
A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name snail is also used for most of the members of the molluscan class Gastropoda that have a coiled shell that is large enough for the animal to retract completely into. When the word "snail" is used in this most general sense, it includes not just land snails but also numerous species of sea snails and freshwater snails. Gastropods that naturally lack a shell, or have only an internal shell, are mostly called slugs, and land snails that have only a very small shell are often called semi-slugs.
Snail
Helix pomatia sealed in its shell with a calcareous epiphragm
Slug
Cornu aspersum – garden snail