• Webster's Revised Unabridged Dictionary
    • n Ianthina (Zoöl) Any gastropod of the genus Ianthina, of which various species are found living in mid ocean; -- called also purple shell, and violet snail.☞ 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.
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Century Dictionary and Cyclopedia
    • n ianthina The representative genus of the family Ianthinidæ; the oceanic violet-snails. One of the best-known species is I. fragilis. They are found floating in shoals on the open seas of warm latitudes, buoyed up by the peculiar float attached to the foot, and are often cast ashore in vast numbers during storms. The animal when irritated pours out a violet secretion, serving to some extent for concealment, like the ink of the cuttlefish.
    • n ianthina [lowercase] A violet-snail.
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Chambers's Twentieth Century Dictionary
    • n Ianthina ī-an-thī′na a genus of gregarious, pelagic gasteropods, having a snail-like shell, but delicate, translucent, and blue in colour.
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Webster's Revised Unabridged Dictionary
NL., fr. L. ianthinus, violet-blue, Gr. ; violet + flower
Chambers's Twentieth Century Dictionary
Gr. ianthinosion, a violet, anthos, a flower.


In literature:

Mr. Macgillivray states that it is furnished with a float in the manner of Ianthina.
"Voyage Of H.M.S. Rattlesnake, Vol. 2 (of 2)" by John MacGillivray
M. ianthina differs in having a conical cap.
"The Mushroom, Edible and Otherwise" by M. E. Hard