Michaelsen, 1920
Description
Large pink worms. Prostomium rounded but bearing thin proboscis. Chaetae two per bundle, sigmoid, with nodulus, sharp-tipped but bearing also tiny, parallel upper tooth; 110-260 µm long. Clitellum in VIII-XXIII, very thick. Long tubular atria with male pores in X, reaching internally to several segments backwards. Two pairs of spermathecae, in VIII and IX, entally connected with oesophagus; ectal pores ventrally in corresponding segments. Unpaired, additional rudimentary atrium of unknown function in IX, with median ventral pore in the same segment. Length 15-50 mm, body diameter 1-1.5 mm, segment number 120-160. Differing from congeners, recorded from NWE, in having small but distinct upper tooth in all chaetae. Some other species with proboscis and similar chaetae, known from eastern Europe, have either one single pair of spermathecae, or two pairs of spermathecae but no unpaired rudimentary atrium.
Burrowing in sediment. Able to swim short distances when irritated.
Distribution
Western Palaearctic.
Ecology
In freshwater, particularly in cooler habitats.
Reproduction
Sexual only. Eggs laid in cocoons attached to substratum with one end.
Literature
Michaelsen, 1920: 130-136, Fig. 1; Cook, 1971a: 260, Fig. 5.9B; Chekanovskaya, 1981: 458-459, Figs 233-234; Kasprzak, 1981: 191, Figs 756-758.