(Müller, 1774)
Description
Comparatively long transparent worms. Dark transversal stripes can occur on anterior segments. Eyes present. Dorsal chaetae beginning from VI, sometimes further rearward, seldom completely lacking. Only one straight, stick-shaped chaeta in dorsal bundles, 128-168 µm long, with rounded or bluntly bifid tip. In ventral bundles, ordinary bifid crotchets, 147-179 µm long in II and 114-158 µm rearward, with equal teeth or with upper tooth slightly longer. In mature individuals blunt curved penial chaetae by 2-3. Length 6-36 mm, segment number in zooids 23-51, in single individuals 35-97.
Crawling on substratum, winding around plant stems. Not able to swim.
Distribution
Holarctic; known also from Japan and South America.
Ecology
In freshwater, particularly on water plants.
Reproduction
Mostly asexual, by paratomy (budding). Mature individuals and sexual reproduction rare or seasonal.
Literature
Müller, 1774: 20-21; Sperber, 1948: 100-101, Figs 10, 26F, Pl. V Fig. 5, Pl. VI Fig. 1; Sperber, 1950: 59, Fig. 9; Brinkhurst and Jamieson, 1971: 327-328, Fig. 7.4F-H; Chekanovskaya, 1981: 244-246, Fig. 111; Hrabe, 1981: 38, Pl. 3 Figs 14-18; Kasprzak, 1981: 134, Figs 399-402.