volute

This example is much richer, yet no less elegant, than the other; the volute, instead of a single spiral, is formed by three; the sculptured echinus beneath is surmounted by a guilloched moulding, and separated from the shaft by a neck […]

Common shells include frog-shells, distorsios, volutes, tulips, murex, cones, olives, marginellas, cowries, augers and the Florida horse conch, the state's official shell, which can grow up to 24in (6 1 cm) long.