Studies on the Ecology of Certain Rumen Ciliate Protozoa Eadie, J. Margaret,, 49, 175-194 (1967), doi = https://doi.org/10.1099/00221287-49-2-175, publicationName = Microbiology Society, issn = 1350-0872, abstract= SUMMARY The times taken by Ophryoscolex tricoronatus and species of the genus Epidinium to establish in the rumens of young animals were found to differ from those of other rumen ciliate species. The antagonistic relationships between certain rumen ciliates were examined in vivo and concurrent experiments were made in small vessels termed vivars which were suspended within the rumen of a sheep. A Millipore membrane separated the rumen contents from the contents of the vivars. Within these vessels it was possible to reproduce population changes first observed in vivo and to determine with certainty that in a population change where Polyplastron multivesiculatum became irreversibly dominant this had been caused by predation by Polyplastron. This organism will eliminate Epidinium, Eudiplodinium maggii, Eremo-plastron and Ostracodinium from a population. The cause, factors affecting it and the ultimate effect on the population are discussed. It was not possible to cause a reversal of the population within a vivar suspended in sheep, but since the prey of Polyplastron still existed and since the reverse change was seen to occur in cattle, this problem still remains unsolved. There was also some evidence of antagonism between Epidinium and Ophryoscolex., language=, type=