I

n.; pl. L. Ianthinæ E. Ianthinas. (Zool.) Any gastropod of the genus Ianthina, of which various species are found living in mid ocean; - called also purple shell, and violet snail. [Written also janthina.] It floats at the surface by means of a raft, which it constructs by forming and uniting together air bubbles of hardened mucus. The Tyrian purple of the ancients was obtained in part from mollusks of this genus.