Gephyrea is a now-dismantled class of marine worms, containing the three modern taxa Echiura, Sipuncula, and Priapulida.^[1] Also Sternaspis, the first described genus in the family Sternaspidae, was at some point assumed to be related to Echiura and therefore included in the Gephyrea.^[2] This class was not monophyletic. Priapulida are now considered a distinct phylum among Ecdysozoa, while the other two taxa are classified as Annelids. The word was created by Quatrefages^[3] from the Greek γέφυρα (géphura) 'bridge', because these animals seemed intermediate between Annelids and Holothurians.^[4]