Invalid names: Arenicolidae Johnston 1835 [empty], Capitellidae Grube 1862 [empty], Cossuridae Day 1963 [empty], Maldanidae Malmgren 1867 [empty], Opheliidae Malmgren 1867 [empty], Orbiniidae Hartman 1942 [empty], Paraonidae Cerruti 1909 [empty], Questidae Hartman 1966 [empty], Scalibregmatidae Malmgren 1867 [empty]