旧きゅう口こう動どう物ぶつ

noun

protostome

Zoological term for animals in which the mouth develops from the first embryonic opening (blastopore). Contrasts with 新口動物 (deuterostome).

See also: 新口動物

• 節せっ足そく動どう物ぶつや軟なん体たい動どう物ぶつは旧きゅう口こう動どう物ぶつに分ぶん類るいされる。

  Arthropods and mollusks are classified as protostomes.