Light microscopy images of Balantidium ctenopharyngodoni. A. Living specimens, showing numerous B. ctenopharyngodoni specimens in the luminal contents of the hindgut. Scale bar = 50 µm. B. Living specimens, showing the general form and vestibulum (arrow). Scale bar = 50 µm. C-D-E. Specimens stained with protargol, showing its somatic kineties (C.) peripheral fibres (pf), (D.) macronucleus(mac) and micronucleus (mic), (E.). Scale bar = 50 µm.