MUREX

any of the marine snails constituting the family Muricidae (subclass Prosobranchia of the class Gastropoda). Typically the elongated or heavy shell is elaborately spined or frilled. The family occurs throughout the world but mainly in the tropics. The many muricids that live in rocky shallows are called rock shells, or rock whelks. The animal feeds by drilling a hole in the shell of another mollusk and inserting its long proboscis. Most species exude a yellow fluid that, when exposed to sunlight, becomes a purple dye. The dye murex (Murex brandaris) of the Mediterranean was once a source of royal Tyrian purple. Another example of the most important genus is the 15-centimetre (6-inch) Venus comb (M. pecten), a white, long-spined species of the Indo-Pacific region. Other members of the Muricidae include small, modestly ornamented shells given various names. The oyster drill (Urosalpinx cinerea) and dwarf tritons (genus Ocenebra) are pests in oyster beds. Drupes (Drupa, Acanthina) are colourful Indo-Pacific shells. Dogwinkles (Nucella) resemble periwinkles.