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Sculptures by Phyllis Bone


Snails and slugs are gastropods in which the mantle cavity is modified to form a lung for breathing air. It may be further modified for breathing under water. Pulmonates undergo torsion and usually bear shells, which lack an operculum. Most are terrestrial or fresh water animals; a few are marine. Pulmonate molluscs are thought to have descended from prosobranch snails living in brackish water e.g. Bithynia tentaculata.