Monotis (English spelling)

Japanese: モノチス（英語表記）Monotis

Representative genus of the bivalve family Monochiidae. There are species with both shells almost identical to each other, and species with the left shell convex and the right shell flat. The shell is thin with well-developed radial ribs. The rim is straight. The byssus foramen in the right shell is small but deep. The small lumen projects diagonally forward. Marine. Index fossil distributed worldwide in the Late Triassic (Norian Stage). In Japan, it is found in the southern Kitakami Mountains, the Kanto Mountains, and the Chugoku Mountains.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

二枚貝綱モノチス科の代表属。両殻はほぼ同形の種類と，左殻凸で右殻が平らな種類とがある。殻は薄く，放射肋が発達している。鉸縁は直線状。右殻の足糸孔は小さいが深い。小耳は斜め前方に出る。海生。三畳紀後期 (ノリアン期) に世界的に分布する示準化石。日本でも北上山地南部や関東山地，中国山地に産出する。

出典　ブリタニカ国際大百科事典小項目事典ブリタニカ国際大百科事典小項目事典について　情報

<<: Monody (English spelling) monody English

>>: Monotype