---

Most likely Chaetogaster setosus. A small Oligochaete species with only simple pointed chaetae on the ventral side. This species is probably one of the smallest freshwater Oligochaete worldwide. Other Chaetogaster species have bifid chaetae and all other oligochaetes have dorsal and ventral chaetae. Did you collect it? I would like to have an ethanol preserved specimen.
It is no Aeolosomatidae for members have bundels of hairs dorsally and ventrally and NO Acanthobdella for those members are strictly North east European.