Bourne, 1891
Description
Small transparent worms. Prostomium with proboscis. No eyes. Hair chaetae similar in all segments, 118-480 µm long, by 1-4, finely serrated. Needle chaetae with two tiny teeth, by 1-4, 23-70 µm long. Ventral chaetae by 2-8, 32-65 µm long; longest in II with upper tooth twice as long, further rearward with upper tooth gradually even shorter than lower one; from VIII on chaetae becoming also shorter and more curved. In some individuals giant ventral chaetae can occur in IV-V: 49-80 µm long and up to 6 µm thick, with particularly long upper tooth. Mature individuals can have thick spermathecal chaetae, 80 µm long, with prolonged teeth, in VI-VII. Length 1.8-8.5 mm, segment number in zooids 12-26, in single individuals 13-26. In freshwater, cosmopolitan. The form devoid of giant ventral chaetae (more common in higher latitudes) has been treated as a separate species, Pristina foreli (Piguet, 1906a).
Crawling on substratum.
Distribution
Cosmopolitan.
Ecology
In freshwater, particularly among macrophytes.
Reproduction
Mostly asexual, by paratomy (budding). Mature individuals and sexual reproduction rare or seasonal.
Literature
Bourne, 1891: 352-353; Sperber, 1948: 230-232, Fig. 24, Pl. XXI Fig. 5; Sperber, 1950: 77, Fig. 28B; Brinkhurst and Jamieson, 1971: 401, Fig. 7.24D-G; Chekanovskaya, 1981: 268-269, Fig. 127; Hrabe, 1981: 60, Pl. 9 Figs 14-16; Kasprzak, 1981: 97-98, Figs 205-208.
As Pristina foreli: Piguet, 1906a: 222-223, Pl. IX Figs 21, 25, 27-28; Sperber, 1948: 229-230, Pl. XXI Fig. 4; Sperber, 1950: 76-77, Fig. 28A; 399-400, Fig. 7.24A-C; Chekanovskaya, 1981: 265, Fig. 125; Hrabe, 1981: 60, Pl. 9 Figs 17-19; Kasprzak, 1981: 98, Figs 209-212.