Gastropod species grow shells in an array of coiled forms which resemble turbans, turrets and trumpets. The digestive organs of the animal are contained inside the shell, while they move around using a flexible foot. Some gastropods such as whelks are carnivores, and feed on other shellfish.

The name ripo matamata refers to the marine snail which has a whirlpool-shaped shell, with radiating points around its edge. This New Zealand species is now relatively rare, but its relative, the pūpū karikawa frequently washes up on Taranaki beaches.