Yantins

Shells are relatively small, 20 to 40 mm long, fragile, spherical-cubar-shaped. Sink thin, without cap and without epidermis. The sculpture of shells is formed only by axial lines of growth. The aperture is wide, irregular in shape, with a curved lower part of the inner lip. The color of the shells varies from bright purple to lilac ^[1] .

The mollusk head is elongated in the form of a short trunk. A mouth opening without jaws, with a radula containing numerous teeth. The eyes are sessile or invisible. The gills are cirrus. The leg consists of two parts: the front leg is tubular due to the bending of the edges, in which the atmospheric air bubbles are surrounded by a mucous secretion and their attachment to the “float” increases it; and the back to which the float rod is attached.

Clams are dioecious. Copulative organs are absent. Partially propagated by eggs. In this case, egg capsules are attached to the underside of the float. Partially give birth to live cubs. The embryo has a lid of the shell, which is covered with shimmering hairs, a sail (velum) and large pigmented eyes.

Pelagic mollusks live on the surface of the open sea over great depths. Widely distributed in the tropical and subtropical regions of the oceans , including the Atlantic Ocean , the Indian Ocean and the Pacific Ocean . From Australia to the Mediterranean and Red Sea , Papua New Guinea , and also on the coast of Hawaii ^[1] . Captured by the currents, they are periodically carried to the coldest areas of the ocean right up to the shores of Ireland and Japan . Also, during storms, shells often take to the coast ^[2]

Shellfish usually drift along the waves with the help of a durable spongy “float”, which is created by the shellfish from viscous mucus and air bubbles ^[1] and having a polygonal shape due to mutual pressure. The float ends with a narrowed stalk, which is attached to the leg of the mollusk ^[3] . Swims upside down ^[3] .

Mollusks feed on siphonophores ^[1] living on the surface of the water, jellyfish of the genus Velella ^[1] and other pelagic invertebrates ^[3] .

In case of danger, with irritation they emit a violet liquid from the gill cavity as a "smoke screen".

The genus includes the following species: ^[4]

• Janthina exigua (Lamarck, 1816)
• Janthina janthina (Linnaeus, 1758)
• Janthina pallida (W. Thompson, 1840)
• Janthina globosa (Swainson, 1822)
• Janthina umbilicata (d'Orbigny, 1841)

In the 1990s, biologist Sol Kaplan ( Eng. Dr. SW Kaplan ) was able to dye the substance that was released upon irritation with tissue previously etched with alum , although dyeing was unstable ^[5] . The results were not published in the scientific literature.

• Knipovich N.M. ,. Yantina // Brockhaus and Efron Encyclopedic Dictionary : in 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.
• Kitrossky, Levi. Do we know thetle? (Eng.) = Do We Know Tekhelet? // NDS Chidushei Torah @ NDS: Yearbook. - Jerusalem, 2003 .-- Vol. 4 . - P. 43-60 . (eng.)