echinopluteus

Japanese: echinopluteus

…The eggs are isoyolk eggs, and cleavage occurs throughout the egg. After repeated divisions and passing through the cyst stage, the larvae become four-armed pluteus larvae (the ones in sea urchins are called echinopluteus) measuring about 0.5 mm in size, and live a floating life. They then grow into eight-armed larvae. About one month after fertilization, a small mass forms inside the larvae's body. …

From [Echinoderms]

…However, some starfishes nurse their young for a period of time, or go directly to adulthood after viviparity. The larvae of sea urchins are called echinopluteus, those of brittle stars are called ophiopluteus, those of starfish are called bipinnaria, and those of sea cucumbers are called auricularia. They have a strong ability to regenerate, and starfishes can regenerate an entire arm from a single one if the central disc is still attached. …

*Some of the terminology that mentions "echinopluteus" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…卵は等黄卵で，卵割は全割。分割を繰り返し，囊胚期を経て，大きさが約0.5mmの4本の腕をもったプルテウス幼生(ウニのものをとくにエキノプルテウスechinopluteusと呼ぶ)になって浮遊生活し，その後成長して8本の腕をもつ幼生になる。受精後約1ヵ月するとこの幼生の体の中に小さな塊ができる。…

【棘皮動物】より

…しかし，ヒトデ類の中で，ある期間保育したり，胎生を経て直接成体になるものもある。ウニ類の幼生はエキノプルテウスechinopluteus，クモヒトデ類の幼生はオフィオプルテウスophiopluteus，ヒトデ類の幼生はビピンナリアbipinnaria，ナマコ類の幼生はアウリクラリアauriculariaと呼ばれている。再生力が強く，ヒトデ類では中央の盤がついていれば1本の腕から全体を再生することもできる。…

※「echinopluteus」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典第２版について | 情報

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