(M. Sars, 1835)
Description:
Body long and cylindrical with 32 segments. Body covered with small filiform or conical papillae.
Prostomium as long as broad, in the middle with a short tip. One pair of relatively large eyes and often an additional pair of very small eyes.
Palps club-shaped, not much longer than the prostomium.
4 pairs of club-shaped gills on segments 2-5, clearly longer than the segment width. 3rd segment dorsolaterally with on each side 1 filiform papilla below the gill.
Ventral chaetae start at the 4th segment. Dorsal chaetae normally start at the 5th segment. The first notopodia with a single denticulate capillary chaeta; the following notopodia with 2-7 of such chaetae. Neuropodia bear 1-2 compound chaetae with a short lamella on the concave side of the curved tip (M. clavicornis-chaeta).
Pygidium rounded, with papillae.
Size:
Up to 7-10 mm for 45 segments.
Colour:
Brownish or blackish pigment in between the segments on the anterior body. Phosphorescent.
Habitat:
Low water, between seaweeds.
Distribution:
North Atlantic up to Mediterranean, Adriatic Sea, northern North Sea, Skagerrak and Kattegat.