Body long, thin and cylindrical, with 40 chaetigers.
Prostomium broadly rounded anteriorly, gradually broadening posteriorly and fused to peristomium. Head not clearly marked off from the first chaetiger. Without ocelli. Nuchal slits semicircular, which open postero-laterally.
Second and third chaetiger with broad anterior collars, dorsally incised and with smooth edges. From chaetiger 15-17 onwards, with posterior collars, incised and with smooth edges. First chaetiger much longer than the head, at least 3x as long as broad, with parapodia close to the anterior border. Next chaetigers shorter, with parapodia in the middle of the segment. Mid-body segments very long, with parapodia close to the posterior border. Posterior chaetigers short.
Chaetigers 2-9 with glandular bands anterior to parapodia. On the 3rd chaetiger also a clear glandular area ventrally, behind the parapodia. Other segments with glandular areas around the parapodia.
Notopodial capillay chaetae with one or two smooth wings. Neropodial hooks in two rows on chaetigers 5-15, posterior chaetigers with hooks in a single row. Last 1 or 2 posterior chaetigers without chaetae. The hooks resemble uncini (R. loveni-detail).
Pygidium very short, cylindrical to conical, with papillae.
Up to 110 mm or more for 40 chaetigers.
Light coloured, older specimens yellowish to yellow-red or brownish to completely black, covered with mud or a few sand grains.
Yellowish to yellowish-brown, up to 9th chaetiger with reddish coloured glandular fields and grey-brown posterior segment endings.
From upper sublittoral down to 1650 m deep, mostly in mud, sometimes in mud mixed with sand or shells.
Arctic, North Pacific, North Atlantic up to Mediterranean, North Sea, Skagerrak, Kattegat, Belt Sea and Öresund and western Baltic Sea.