Body elongated, oval, slightly tapering at both ends.
Prostomium, rounded anteriorly, with tiny papillae and 2 pairs of filamentous antennae and one median one. No eyes.
First segment with one pair of small filamentous tentacular cirri and many small papillae. Following segments dorsally with one transversal row of 2-4 big tubercles, in the middle of the segment. Dorsal and ventral surface with small papillae.
Parapodia short with a triangular terminal papilla, a short, ventral cirrus, many small papillae and up to forty chaetae with smooth falciger blades and aciculae, weakly bent at the tip (S. philippi-detail).
Up to 15 mm long for 28 segments.
In alcohol yellowish or whitish with brownish tubercles.
Muddy and sandy sediments and between stones and shells, from 0 to 200 m.
North Sea, Skagerrak, Kattegat, Öresund, Arctic.