(Audouin & Milne-Edwards, 1833)
Body quite broad, prostomium pointed or rounded, with four eyes in a curved line or without eyes, with a small median antenna, between 2 long palps. Caruncle reaching the posterior margin of chaetiger 1.
Notopodial postchaetal lobes in segment 1 small and oval, in the following segments long and narrow and completely fused to the gills, from segment 50-60 onwards, small and oval and almost fully separate from the gills. Neuropodial postchaetal lobes in anterior segments short and rounded, from segment 70 onwards bilobed, then in posterior segments simple again.
Gills cirriform, from segment 2 to almost to the posterior end.
Anterior parapodia with capillary chaetae only, from neuropodium 50-67 and from notopodium 50-70 onwards also hooded hooks present. These unidentate or with a small accessory tooth (S. foliosa-detail).
Pygidium with a single lobe.
Up to 160 mm for 250 segments.
Anteriorly red, posteriorly dark green.
At low water, in pure or slightly muddy sand. Live in horizontal burrows, but do not construct real tubes. Down to 50 m.
Arctic, North Pacific, North Atlantic to Mediterranean, North Sea to Öresund.