xenoturbellan
A zoological term for a small group of simple, worm-like marine animals classified as basal deuterostomes. Rare in everyday language; used mainly in biology contexts.
Xenoturbellans are primitive animals that live in the mud on the seafloor.
The Japanese name 珍渦虫 (chin'uzumushi) literally means 'rare whirlpool worm', likely referring to its unusual appearance and habitat. The exact derivation is uncertain.