(O.F Müller, 1776)
Body long, anteriorly broad and flat, posteriorly slightly flattened dorsally and rounded ventrally.
Prostomium sharply conical, longer than broad, with 2 small eyes.
Thorax with 12-22 chaetigers. Thoracic notopodia with a small, conical postchaetal lobe, with an acicula and a bundle of capillary chaetae. Thoracic neuropodia are swollen tori with small, conical postchaetal lamellae, many capillary chaetae and characteristic hooks. One to two subpodial papillae on the last 1-5 thoracic segments and 1-7 anterior abdominal segments; next abdominal segment with a kind of subpodial collar.
Abdominal notopodia with simple postchaetal lobes, with aciculae, capillary and forked chaetae. No interramal cirrus. Abdominal neuropodia bilobed, with aciculae, a few capillary chaetae and a small ventral cirrus (S. armiger-detail).
Gills, tongue-shape or lanceolate, start at chaetiger 9-17. In the abdomen, gills, noto- and neuropodia all set dorsally.
Pygidium with two long cirri.
Up to 120 mm for over 200 segments.
Living animal bright orange or pink.
In all kind of soft bottoms; eulittoral to 2000 m; also in brackish water. The burrows are long and lined with mucus; usually 10-15 cm deep in the sediment.
World-wide. North Sea to Baltic (Gotland-Becken).