Abstract
There is an unusual group of protozoa to be found in the oxygen-poor and oxygen-deficient waters of sewage treatment plants. Most of these are apparently facultative anaërobes. A few appear to be obligatory anaërobes. It is shown that the presence of dissolved oxygen in sewage allows Opercularia to thrive, while the absence of oxygen is fatal to this protozoön, if the condition endures for several days. The reverse conditions are found to obtain for Trepomonas, except that active aëration of the water is quickly fatal. Six new species of protozoa from sewage or polluted waters are described.

This publication has 0 references indexed in Scilit: