I have written this book because there is, as in almost all supraspecific ciliate taxa, an ur gent need for an up-to-date revision of the oxytrichids, which are common in terrestrial, limnetic, and marine biotopes. The last comprehensive, illustrated guides to this group of hypotrichs were provided by KAHL (1932) and SmLER (1974b); however, as regards syn onymy and faunistics, these works are outdated and not as detailed as EHRENBERG'S out standing book from 1838. In KAHL's revision, the oxytrichids sensu stricto are described on about 30 pages, whereas in the present book the systematic...