Eversible pharynx with 5 pairs of maxillae. At least one but as many as 5 occipital antennae present. No frontal antennae. One pair tentacular cirri in some species. Parapodia have a reduced notopodium which might only be represented by a gill, dorsal cirrus and possibly a notoaciculum. Setae may include the following, simple winged, simple serrated, sub-acicular hooks, compound falcigers and compound spinigers.