noun
gastrotrichs
A phylum of microscopic, bristled, wormlike aquatic animals. Technical term used in zoology.
腹毛類は淡水や海の砂の間に生息する微小な動物だ。
Gastrotrichs are tiny animals that live in freshwater and between sand grains in the sea.
Compound of 腹 (belly) + 毛 (hair) + 類 (group, category), referring to the ventral cilia used for locomotion. The exact historical derivation is uncertain.