[Metacercaria of Cyathocotyle prussica Mühling, 1896 (Cyathocotylidae, Trematoda)].

Cyathocotylid larvae were found in the musculature of Gobio gobio and Leuciscus leuciscus from the cut-off part of the Ishim river (West Sibiria). Experimental infection of domestic ducklings has shown that the metacercariae are the larvae of C. prussica. They differ from the other known larvae of Cyathocotylidae from musculature of fishes of Europe and Asia in having a larger Brandes'organ.