noun
elongate janthina; Janthina globosa
A species of violet sea snail. The name is usually written in katakana as ルリガイ.
ルリガイは美しい紫色の殻を持つ巻貝です。
The elongate janthina is a sea snail with a beautiful purple shell.
The name ルリガイ (瑠璃貝) literally means 'lapis lazuli shell', referring to its violet-blue color. The exact derivation is uncertain beyond this descriptive compound.