Didinium captures Paramecium. It is not unusual for an undersized Didinium to attempt to ingest a much larger Paramecium. In this case, the organisms were preserved before the outcome could be determined. This micrograph was taken in 1968 by G. Antipa on a Cambridge Mark IIA operating at 20kV. The negative magnification is 440X. Further details are available at Wessenberg, H. and Antipa, G. 1970. Capture and ingestion of Paramecium by Didinium nasutum. J. Protozool. 17:250-270.