noun
protostome
Zoological term for animals in which the mouth develops from the blastopore. Contrasts with 旧口動物 (deuterostome).
See also: 旧口動物
前口動物には節足動物や軟体動物が含まれる。
Protostomes include arthropods and mollusks.
旧口動物 (deuterostome) is the contrasting group where the anus forms from the blastopore; includes vertebrates and echinoderms.
Compound of 前 (front) + 口 (mouth) + 動物 (animal), calque of the taxonomic term 'protostome' (from Greek 'proto-' first + 'stoma' mouth).