Ehrenberg, 1831
Description
Small transparent worms. Prostomium with proboscis. No eyes. Hair chaetae in III extremely long, 215-800 µm; in the other segments 70-380 µm, by 1-4, serrated (long chaetae in III can be smooth). Needle chaetae with simple sharp tip (sometimes fine bifurcation observed under very high magnification), by 1-5, 35-72 µm long. Ventral chaetae by 3-9, in II-III 55-93 µm long, with upper tooth twice as long as lower one (sometimes in III particularly thick, with upper tooth up to 3 times as long); further rearward ventral chaetae 49-69 µm long, the ratio of tooth length 1.5. Mature individuals can have thick spermathecal chaetae with prolonged teeth in VI. Length 3.5-6 mm, segment number in zooids 10-18, in single individuals 15-33.
Crawling on substratum.
Distribution
Cosmopolitan. Several subspecies of disputable validity, have been described from different continents.
Ecology
In freshwater, particularly among macrophytes.
Reproduction
Mostly asexual, by paratomy (budding). Mature individuals and sexual reproduction rare or seasonal.
Literature
Ehrenberg, 1831: 112; Sperber, 1948: 236-237, Pl. XXI Figs 2, 6; Sperber, 1950: 77, Fig. 28C; Brinkhurst and Jamieson, 1971: 402-405, Figs 7.21J, 7.25E-M; Chekanovskaya, 1981: 265-268, Fig. 126; Hrabe, 1981: 59; Kasprzak, 1981: 96-97, Figs 199-204.