(Savigny, 1826)
Description
Small earthworms. Forebody dark, hindbody greyish. Chaetae very closely paired in bundles, especially on tail, giving thus it a quadrangular appearance. Male pores in XIII (seldom in XII, XIV, or XV). Clitellum from XX...XXIV to XXIV...XXVI, tubercula pubertatis as ridges in XXI...XXV to XXIV...XXVII, respectively. Length 15-95 mm, body diameter 1.5-4 mm, segment number 37-165. Several forms of this variable taxon with different positions of male pores and clitellum have been described as separate species or subspecies. Differing from the other earthworms in the variable, mostly anterior, position of male pores (always in XV in the other species), relatively anterior position of clitellum, and four-square tail portion. In the aquatic species of another genus, Helodrilus, the clitellum begins in the same anterior segments but it is much longer there.
Burrowing in soil and sediment.
Distribution
Western Palaearctic, introduced also into many other temperate regions.
Ecology
In shallow freshwater and in wet soil of shores.
Reproduction
Sexual only, often parthenogenetic. Eggs laid in cocoons.
Literature
Savigny, 1826: 184; Eisen, 1874: 47; Orley, 1885; Rosa, 1886: 680; Michaelsen, 1890: 7; Graff, 1953: 54, Fig. 55; Bouché, 1972: 215; Plisko, 1973: 124-128, Figs 138-144; Reynolds, 1977: 84-87, Fig. 26; Chekanovskaya, 1981: 490-491, Fig. 249; Sims and Gerard, 1985: 90-93, Figs 29-30; Omodeo and Rota, 1991: 173-174.