Branchiopods - Branchiopods

Japanese: 鰓脚類 - さいきゃくるい（英語表記）branchiopod

A general term for crustaceans classified as the Branchiopoda. They are divided into the Sarsostraca subclass and the Phyllopoda subclass. They are a group with a primitive body plan among extant crustaceans, with about 1200 known species. Very few are marine, and most live in relatively shallow freshwater areas. The basic common body plan is that they have bifurcated flat appendages, the outer branches of which form gills and help with breathing. The Sarsostraca subclass consists of the Anostraca order, and the Notostraca subclass is divided into the Notostraca order and the Diplostraca order. The Anostraca order, as typified by the Notostraca shrimp, has no carapace and has a long, cylindrical body. In the Notostraca order, the front half of the body is covered by a carapace, as seen in horseshoe shrimp. The Bivalve order includes the clam shrimp and water fleas, and is covered by two bivalve-like carapaces on the left and right. Daphnia are important as natural food for fish. (→ Arthropods)

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

Japanese:

鰓脚綱 Branchiopodaとしてまとめられる甲殻類の総称。サルソストラカ亜綱 Sarsostracaと葉脚亜綱 Phyllopodaに分けられる。現生の甲殻類のなかで原始的な体制をもつ一群で，約 1200種が知られている。海産はごく少数で，ほとんどが淡水の比較的浅い水域にすむ。基本的な共通体制は，二叉型の扁平な付属肢をもち，その外枝が鰓となって呼吸に役立っていることである。サルソストラカ亜綱は無甲目 Anostracaからなり，葉脚亜綱は背甲目 Notostraca，双殻目 Diplostracaに分けられる。無甲目はホウネンエビに代表されるように甲をもたず，体は細長い円筒形である。背甲目ではカブトエビにみられるように体の前半部が背甲で覆われている。双殻目はカイエビやミジンコの類で，左右 2枚の二枚貝状の甲に包まれている。ミジンコ類は魚類の天然餌料として重要である。（→節足動物）

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