Barnacles - barnacle

Japanese: 蔓脚類 - まんきゃくるい（英語表記）barnacle

A general term for crustaceans belonging to the class Cirripedia of the subclass Coleopidae of the class Gnathopoda. They are broadly divided into the class Chrenidae, which bore into corals and shells, the class Ploce, which parasitize decapod crustaceans, and the class Barnacles, which attach themselves to rocks and large animals in the sea. In the strict sense, barnacles are the only ones called Cirripedia. Barnacles are divided into the class Ploce, which has a stalk (order Stalked), and the class Ploce, which does not have a stalk (order Sessile). All are marine. The hatched nauplii live a planktonic life, but when they become bivalve-like cypris, they live on the seabed and metamorphose into their adult form in a fixed location. All adults are sessile or parasitic. Sessile species secrete calcareous shell plates on the outside and place their bodies inside in an inverted form. The trunk is incompletely segmented. The thorax has six pairs of appendages called cirripedia, which are well developed. Fossils have been found since the Silurian period of the Paleozoic era, but there are about 800 extant species. (→ Gnathopoda, Arthropods)

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

Japanese:

顎脚綱鞘甲亜綱蔓脚下綱 Cirripediaに属する甲殻類の総称。サンゴや貝殻に穿孔するツボムシ類，十脚甲殻類に寄生するフクロムシ類，海中の岩や大型動物に固着するフジツボ類に大別される。狭義には，フジツボ類だけを蔓脚類と呼ぶ。フジツボ類は柄のあるエボシガイ類（有柄目）と柄のないフジツボ類（無柄目）に分けられる。すべて海産。孵化の幼生ノープリウスは浮遊生活をするが，二枚貝状のキプリスになると海底におり，場所を定めて成体形に変態する。成体はすべて固着あるいは寄生性。固着性の種はその外側に石灰質の殻板を分泌し，体を内部に倒立させた形で納める。胴部の分節は不完全。蔓脚と呼ばれる胸部 6対の付属肢がよく発達する。化石は古生代シルル紀以来出土するが，現生種は約 800種。（→顎脚類，節足動物）

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