(Bretscher, 1903)
Description
Small white, sometimes greenish, worms. Chaetae by 3-10, most numerous in ventral bundles, sigmoid, simple-pointed, with nodulus, 56-64 µm long, absent ventrally from XII. Male pores in XII; clitellum in XII-1/2 XIII, clitellar glands arranged in transverse rows. Interior characters: Pharyngeal glands in two pairs; dorsal lobes at 4/5 and 5/6 connected or not with each other, ventral lobes in V and VI. Coelomocytes mostly broadly spindle-shaped, sometimes also oval or roundish, either granular or generally brown, often very abundant. Chloragogen tissue consisting of large cells, covering oesophagus from VI, with some cells already in V. No appendages on digestive tube. Blood colourless or light red; dorsal blood vessel reaching backward up to XIII. Spermathecae not connected with oesophagus. Spermathecae with roundish or oval ampulla containing either ring-shaped or irregular sperm; duct of the same length or up to 2-3 times as long as ampulla, with ectal pore in 4/5. Ampulla can be limited to V or reach further backward up to VIII. No glands at spermathecal pores. Male funnels small, funnel-shaped, without distinct collar. Vasa deferentia not ectally dilatated. A crown of small gland cells surrounding male pore. Eggs in clitellar region only. Length 2-7 mm, segment number 18-28. This species is described as very variable, possibly consisting of different taxa. Can be distinguished from congeners only on the basis of internal anatomy.
Burrowing in sediment.
Distribution
Western Palaearctic, recorded also from the St. Lawrence River in North America.
Ecology
In freshwater, in wet or moist soil.
Reproduction
Sexual, with eggs laid in cocoons.
Literature
Bretscher, 1903: 17; Nielsen and Christensen, 1959: 38-39, Figs 15-18; Kasprzak, 1986: 109-111, Figs 225, 252-260.