Ekologiczna i geograficzna zmienność pierwotniaków w świetle badań faunistycznych

On the example of ciliates of the genus Trichodina the role of extensive faunistic investigation for recognition of morphological variation in parasitic Protozoa is considered. In the paper the results of studies on Trichodina ranae, T. reticulata, T. pediculus and Semitrichodina sphaeronuclea f. macrodentata are summarized with particular attention paid to ecological and geographical aspects of the variation. The evolutionary aspect of these studies is also emphasized.