Polynoidae are a group of Phyllodocida that along with taxa such as Aproditidae, Sigalionidae and Eulepethidae are known as scale-worms. In these taxa the dorsal cirri of some segments, often evert second segment becomes expanded into a broad flap known as elytrae. Scaleworms have four jaws associated with the proboscis and eversion is simialr to other Phyllodocida. Scaleworms represent one of the most diverse groups of polychaetes and are very commonly found living in association with other organisms, particularly echinoderms.