In a natural but newly reconstructed pond the presence of P. biaurelia was revealed. The previous studies conducted in 1992 did not reveal the occurrence of any species of the Paramecium aurelia complex here.
E. Przybos, Department of Experimental Zoology, Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Slawkowska 17, 31-016 Krakow, Poland, e-mail:przybos@isez.pan.krakow.pl