Thorax cylindrical, abdomen tapering slightly towards pygidium. Animal with 27 chaetigers.
Prostomium broadly rounded with many eyespots.
Gills in two nearly continuous groups; three gills of each group in a transverse row, the fourth one just behind the middle one of the three.
Chaetae of segment 3 small, about the size of normal notopodial chaetae, 15-20 on each side. Fifteen thoracic segments with notopodia with capillary chaetae, the 13th pair of notopodia elevated and transformed into transverse, narrow vertical wings, nearly meeting at middorsum. Notopodial chaetae of the 13th pair of notopodia with long, plumed tips, arranged in a row along upper edge of notopodium. Other notopodial chaetae are normal capillaries (S. sulcata-detail). Twelve thoracic and twelve abdominal uncinigerous segments. Uncini with three vertical rows of teeth with 4-5 teeth in each row. Pygidium with two short lateral cirri.
Up to 20 mm.
A thin layer of secretion encrusted with mud.
In alcohol light brownish red.
On mud, clay or sand, or mixed bottoms; 12-500 m.
Eastern North Atlantic to West Africa, Mediterranean. Barents Sea, south and west Norwegian coast to Trondelag, Skagerrak, Kattegat, Swedish west coast, the Öresund.