noun
annulosan
A zoological term for a member of the Annulosa, an obsolete grouping of segmented invertebrates. Rare and primarily of historical or taxonomic interest.
環節動物という分類は、現在ではほとんど使われていない。
The classification 'annulosan' is hardly used today.
環形動物 refers to annelids (segmented worms), a modern phylum, while 環節動物 is an obsolete term for a broader group that included annelids and arthropods.
From 環節 (segment) + 動物 (animal), a calque of the taxonomic name Annulosa.