Summary
1. A culture system was designed and constructed to fill the need for a constant source of planktonic copepods that can be harvested routinely for experimental or feeding requirements.
2. The ciliate, Euplotes vannus, has been found effective in limiting increase and detrital accumulation.
3. Foam separation effectively limited accumulation of dissolved waste products.
4. Large populations of Acartia clausi and Acartia tonsa have been maintained in culture by the method described here for 14 and 10 months, respectively. Acknowledgements. I wish to express my sincere thanks to assistance throughout construction and trial the culture Dr. DAVEY his ascorbate acid assay on culture medium and to D. MoNABB for DOC anal of culture and selected samples; to Dr. A. C. BORROR for identification of the ciliate; and to Dr. R. L. STEELE for providing ph plankton food cultures.