(Lastockin, 1927)
Description
Small transparent worms. No proboscis, no eyes. Dorsal bundles begin from II, with 1-2 smooth hair chaetae, 85-155 µm long, and 1-2 needle chaetae, 25-52 µm long, being the longest in IV-V. In ventral bundles 3-6 chaetae, 31-45 µm long, with distal nodulus, upper tooth becoming shorter in posterior segments. In mature specimens, single modified penial chaetae in VIII. Intestinal dilatation in 1/2 VI-1/2 VII. Transversal blood vessels form plexus in II-V. Length 3-6 mm, segment number in the first zooid 11-12, in the entire worm 12-23. The arrangement of the anterior blood vessels, as well as the segment number distinguish this species from Pristinella menoni, a congener with similar chaetae.
Crawling on substratum.
Distribution
Almost cosmopolitan.
Ecology
In freshwater.
Reproduction
Mostly asexual, by paratomy (budding). Mature individuals and sexual reproduction rare or seasonal.
Literature
Lastockin, 1927: 69, Figs 1-2; Sperber, 1948: 217-220, Fig. 23A-C, Pl. XIX; Sperber, 1950: 75-76, Fig. 27A-C; Brinkhurst and Jamieson, 1971: 393-394, Fig. 7.22F-H; Chekanovskaya, 1981: 269-271, Fig. 128; Kasprzak, 1981: 98-99, Figs 213-220.