noun
deuterostome
A zoological term for animals in which the first embryonic opening becomes the anus. Contrasts with 旧口動物 (protostome).
See also: 旧口動物
ヒトを含む脊椎動物は新口動物に分類される。
Vertebrates, including humans, are classified as deuterostomes.
旧口動物 (protostome) is the contrasting group where the first embryonic opening becomes the mouth.
From 新 (new) + 口 (mouth) + 動物 (animal), referring to the embryonic development where the second opening becomes the mouth.