What is "gephyrea"

Gephyrea \Ge*phyr"e*a\, n. pl. [NL., fr. Gr. ? a dam, a bridge.] (Zo["o]l.) An order of marine Annelida, in which the body is imperfectly, or not at all, annulated externally, and is mostly without set[ae].

Gephyrea is a now-dismantled taxon that was considered to be a class of annulated worms, containing the three modern phyla Echiura, Sipuncula, and Priapulida.