Coronate Dog Whelk (Nassarius coronatus) Gastropods form the largest class of molluscs and include many well-known groups such as cowries, cone snails, tritons, periwinkles and whelks. To date approximately 950 species of gastropods have been recorded from the Bay. In general they are characterised by a head (bearing a pair of eyes and a pair of tentacles), a large (creeping) foot and a visceral mass all housed in a spiral, unchambered shell. The class also includes many forms in which the adult shell is cap-shaped (true limpets, false limpets), reduced, internalised or missing (sea hares, side-gilled slugs, nudibranchs). In most gastropods with a well-developed shell, the aperture of the shell is usually sealed by a trapdoor-like structure (operculum) when the animal retracts. In cowries, the shell aperture is reduced to a slit guarded by several tooth-shaped projections, thus eliminating the need for an operculum.
Queensland Museum's Find out about... is proudly supported by the Thyne Reid Foundation and the Tim Fairfax Family Foundation.