Echiuroidea is an order of annelids in the class Polychaeta. Families Suborder Bonelliida Bonelliidae Lacaze-Duthiers, 1858 Ikedidae Bock, 1942 Suborder Echiurida Echiuridae de Quatrefages, 1847 Thalassematidae Forbes & Goodsir, 1841 Urechidae Monro, 1927 References Echiurans Protostome orders