軟體動物類
A lid or flap covering an aperture, such as the gill cover in some fishes or the horny shell cover in snails or other mollusks. 鰓蓋覆蓋在一孔或縫隙上的蓋，如一些魚類的鰓或覆蓋在蛇或其它軟體動物身上的角質(zhì)殼
Any of various mollusks that bore into soft rock or wood. 鉆蛀蟲鉆入松軟巖石或木頭中的軟體動物
A smooth, lustrous, variously colored deposit, chiefly calcium carbonate, formed around a grain of sand or other foreign matter in the shells of certain mollusks and valued as a gem. 珍珠在幾種軟體動物的貝殼中，圍繞著一粒沙子或其他外來物質(zhì)形成的一種光滑、有色澤、具有不同顏色且主要是碳酸鈣的沉積物，被珍視為寶石
