Ciliophora

This species closely resembles Colpidium colpoda which is included within the key to sewage ciliates. The diagram in Foissner and Berger (1996) illustrates the differences between the two species. Colpidium kleini tends to be smaller and slimmer than Colpidium colpoda. Other illustrations can be found in Ganner and Foissner (1989).