Jagersten, 1952
Description:
Tentacles extend to segment 3 if directed posteriorly (550-650 µm long). Two so-called statocysts; no eyes in adult individuals. Nuchal organs large, oval, dorsolateral grooves. Prostomium with transverse ciliary bands, one behind each nuchal organ. Two well-developed, segmentally arranged, transverse, incomplete rings of ciliary tufts; additional scattered tufts. Females with lateral ciliary bands in segment (8) 10-14; not observed in animals from Helgoland. Epidermis with numerous glands, especially of the bacillary type, distributed most densely ventrally and ventrolaterally. Two well-developed, adhesive pygidial lobes that resemble those of Protodrilus adhaerens . Salivary glands in anterior 10-12 segments of males and in 18-20 segments of females.
Fertile region in males begins in segment 10 or 11, in females in segment 12. Four pairs of spermioducts in segments 11-14. Lateral organs extending from segment 7 to 15; in segment 7 only ciliary pits. No oviducts.
Size:
Up to 4-7 mm for 35-50 segments.
Colour:
Transparent; without colour except for the faintly reddish pharyngeal region.
Habitat:
Intertidal and subtidal shell gravel, and fine to coarse sediments.
Distribution:
North Sea (Helgoland), English Channel, Skagerrak (Swedish west coast, Gullmarfjord), Mediterranean (Naples).