Morning glory - Violet snail

A gastropod shell of the family Ploceidae in the class Gastropoda of the phylum Mollusca. It lives a planktonic life, and is widely distributed in temperate and tropical oceans around the world. It is snail-shaped, with a shell height of about 20 mm. Its shell is thin and brittle, pale purple on top and deep purple-blue on the bottom. The opening of the shell is wide and has no lid. It is proto-male, with the female being larger. The shell secretes mucus from the soles of its feet, takes in air, and creates bubbles, which it then lives suspended from a raft of connected swim bladders, feeding on siphonomedusae such as the porcupine jellyfish. A closely related species is the planktonic blue-and-white turban Violetta globosa , and both species are often washed ashore after strong winds.

[Takashi Okutani]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

軟体動物門腹足綱アサガオガイ科の巻き貝。一生浮遊生活をし、世界の温帯、熱帯の海洋に広く分布している。殻高20ミリメートルぐらいでカタツムリ形。殻は薄質でもろく、上面は淡紫色で、底面は濃紫青色。殻口は広く、蓋(ふた)をもたない。雄性先熟で雌のほうが大きい。軟体は足裏から粘液を分泌し空気を取り込んで泡をつくり、それを連結したうきぶくろの筏(いかだ)の下につり下がったようにして生活し、ギンカクラゲなどのクダクラゲ類を常食としている。近縁種にやはり浮遊性のルリガイVioletta globosaがあり、ともに大風のあと、しばしば海岸に漂着する。

［奥谷喬司］

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