Body long and thin.
Prostomium rounded pentagonal with four eyes with lenses, in a trapezoid arrangement. Often with two ocelli. Palps rounded triangular, longer than the prostomium, extending as two long and broad lips. All three antennae similar, oval or club-shaped, median antenna sometimes a little longer.
Tentacular cirri like the antennae or smaller. Dorsal cirri oval and as long as the parapodial lobes or a little smaller, missing on the second parapodium. Ventral cirri smaller. Acicula with a terminal button.
Blades of compound chaetae of different structure, 2 or 3 needle-like chaetae, the others short. Upper simple chaetae present on all parapodia. Posterior parapodia with an additional lower simple bidentate chaetae.
Pharynx with one anterior tooth.
Body up to 10 mm long for 62 segments.
On mud or sand.
Pacific, Atlantic Ocean to the Mediterranean, southern North Sea, Skagerrak and Kattegat.