Body long and slender. Prostomium elongate, oval to conical. Ventral pair of antennae somewhat longer than dorsal. Proboscis with two mediodorsal and two lateral rows of papillae, distally and ventrally only wrinkled ridges. Often the proboscis is irregularly scattered with papillae, with two lateral papillae at the anterior edge. Ventral pair of tentacular cirri longer than dorsal.
Dorsal cirri of anterior segments more or less asymmetrical, oval, somewhat longer than broad or broader than long, those of mid-body strongly asymmetrical, almost kidney-shaped, up to 2 1/2 times as long as broad; posterior ones asymmetrical, oval, often somewhat longer than broad (E. spetsbergensis-parapodium). Terminal end of chaetal shaft symmetrical with one large tooth and a few smaller ones on each side. Blades long and slender. Ventral cirri longer than parapodial lobes. Pygidial cirri finger-like.
Up to 100 mm for 200 segments.
Living animal dorsally with reddish banding and dark dorsal cirri; ventrally green. In alcohol almost colourless.
On all substrata; upper sublittoral to 400m.
Arctic, North Pacific, North Atlantic, northern North Sea to Öresund.