へた 蓋 鰓蓋
a hard flap serving as a cover for (a) the gill slits in fishes or (b) the opening of the shell in certain gastropods when the body is retracted
(a)魚の鰓孔、または、(b)本体が格納されるとき腹足類の殻の開口部、に対する覆いとして役立つ堅い蓋