any of a genus (Murex) of flesh-eating snails, found in warm salt waters and having a rough, spiny shell: some species yield a purple substance formerly valued as a dye
See murex in American Heritage Dictionary 4
(myo͝orˈĕks)
nounpl.mu·ri·ces(myo͝orˈĭ-sēzˌ) or mu·rex·es
Any of various marine gastropods of the genus Murex common in tropical seas and having rough spiny shells, especially M. trunculus, the source of Tyrian purple.