Rock shell - Rock shell

A gastropod shell of the family Muricidae in the phylum Mollusca. It is one of the most common shells found on intertidal reefs from southern Hokkaido to Kyushu and the western Pacific Ocean. It is a short, spindle-shaped shell 40 mm high and 25 mm in diameter, with a gray-blue surface and a row of large black warts. The shell opening is oval with a black interior and yellowish-white markings on the edge. The axis lip is also yellowish-white, the operculum is brown, and the nucleus is closer to the outside. In summer, they gather in large numbers on the underside of rock shelves and lay many small, vase-shaped egg capsules. They are carnivorous, drilling holes in and killing and eating rock-dwelling oysters, oysters, and barnacles. Their meat is spicy, so the character "nishi" (spicy spiral) is used.

[Takashi Okutani]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

軟体動物門腹足綱アクキガイ科の巻き貝。北海道南部から九州および西太平洋の潮間帯の岩礁にもっとも普通にみられる貝の1種。殻高40ミリメートル、殻径25ミリメートルの短い紡錘形、殻表は灰青色で大きな黒いいぼの列がある。殻口は卵円形で内面は黒く、縁には黄白色の斑紋(はんもん)がある。軸唇も黄白色を帯び、蓋(ふた)は褐色で、核は外側に寄る。夏季に岩棚(いわだな)の下面に多数集まって、小さな花瓶形の卵嚢(らんのう)を多数産み付ける。肉食性で、岩礁にすむケガキやマガキ、フジツボ類に穴をあけて殺して食べる。肉は辛いのでニシ（辛螺）の字をあてる。

［奥谷喬司］

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