Tentacles relatively long (up to 900 µm), when directed backwards reaching segment 5. Two round so-called statocysts in anterior part of prostomium, between the tentacles, and very close to each other. No eyes in adults. Head region with several incomplete ciliary bands and usually three rings in pharyngeal region. Two segmentally arranged, transverse ciliary rings, one near the anterior septum, the other somewhat behind the middle of the segment. Four types of epidermal glands, of which a round yellowish gland is very numerous. Salivary glands difficult to recognize in anterior segments; usually extending to segment 17, sometimes only to segment 12.
Fertile region in males from segment 12 posteriorly, in females from segment 10 or 12. Lateral organs forming continuous ciliated grooves, bordered by glands, from segment 8 to 16; in segment 7 only an isolated ciliated pit. Four pairs of spermioducts in segments 12-15. No oviducts.
Up to 4-5 mm for 30-36 segments.
Pharyngeal region faintly reddish; yellowish around nuchal organs.
Subtidal coarse sediments.
English Channel, Skagerrak (Swedish west coast, Gullmarfjord) and Mediterranean.