(Malmgren, 1867)
Description:
Body dorso-ventrally flattened, anteriorly and posteriorly tapered.
Prostomium rounded to triangular. Eyes medium-sized. Nuchal papilla in a distinct; deep ligula on the collar around prostomium.
Proboscis proximally covered with minute papillae and a group of about 4-8 large papillae basally on each side of prostomium, distally with six rows of tubercles. Terminal ring not observed.
Tentacular cirri of segment 1 reaching about segment 5. Dorsal tentacular cirri of segments 2 and 3 reaching about segment 8. Ventral tentacular cirri as long as those of segment 1 or slightly shorter.
Chaetae present from segment 3. Dorsal cirri of median segments oval, on distinct cirrophores. Parapodial lobes narrow, slightly asymmetrical with upper part larger than lower. Terminal end of chaetal shaft asymmetrical with teeth on one side longer than on other. Blades long and slender. Ventral cirri with rounded ends, as long as or slightly shorter than parapodial lobes.
Pygidial cirri cylindrical, with rounded ends, about twice as long as broad. Minute median pygidial papilla present (P. kosteriensis-detail).
Size:
Up to 85 mm for 155 segments.
Colour:
Living animals white with reddish-brownish pigment forming transverse bands across dorsum. Eyes clear red. Pigmentation retained to a varying degree in preserved specimens with eyes brownish-black.
Habitat:
Muddy sand or mixed sediments with mud, sand, shells and stones. From about 10 m downwards.
Distribution:
North Atlantic up to Mediterranean, northern North Sea, Skagerrak and Kattegat.