||I*an"thi*na (?), n.; pl. L. Ianthinæ (#), E. Ianthinas (#). [NL., fr. L. ianthinus violet-blue, Gr. &?;; &?; violet + &?; flower.] (Zoöl.) 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.]

&fist; 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.