Cragin, 1887
Description
Small worms. Prostomium roundish, slightly broader than subsequent segments, ciliated field restricted to ventral side. Cutaneous glands evenly distributed, olive green, roundish or irregular. Chaetae of two kinds. Hair chaetae flexible, slightly curved, of different lengths (90-180 and 30-80 µm), 0-6(8) per bundle. Sigmoid chaetae thin, either smooth or with a few small denticles on concave side on distal portion, 45-70 µm long, 0-4 per bundle, usually lacking in II. Total number of chaetae per bundle 2-7(8). Length of a chain of 2-3 zooids, up to 3 mm; length of the first zooid up to 2 mm, segment number in a zooid 9-10, in a single individual 7-13. Differing from the other green congeners in having simple-pointed sigmoid chaetae beyond hair chaetae.
Gliding on substratum.
Distribution
Europe, North America.
Ecology
In freshwater.
Reproduction
Asexual reproduction by paratomy (budding) prevailing. Maturing seldom.
Literature
Cragin, 1887: 31; Kenk, 1941: 1-3, Pl. I Figs 1-2; Bunke, 1967: 246-247, Fig. 22; Van der Land, 1971: 683-684, Figs 13.1G,2A; Kasprzak, 1981: 81-82, Figs 129-131.