EN
A new cestode species from the genus Fimbriaria Froelich, 1802 is described. The parasites were found in the duodenum of Aythya fuligula L. and A. nyroca Güld. Described here new species differs from those previously recorded mainly by the mode of egg evacuation from gravid strobila: the Fimbriaria sarcinalis eggs leave the uterus in large irregular packets. Negative results of experimental infection of Acanthocyclops viridis and Macrocyclops albidus (Copepoda) considered as potential intermediate hosts of this new species of cestode are also described and discussed.