A high resolution view of a dividing Didinium nasutum. This large ciliate is capable of engulfing Paramecium. It has a thick ectoplasm containing numerous mucocysts embedded in its extensive epiplasm. It's external surface is coated with a layer of bacteria in this dividing cell. The cytoplasm is relatively compact under the conditions of fixation used. Electron opaque vacuoles are scattered in the cytoplasm. (For a more detailed report see Wessenberg and Antipa, Protistologica 4:427-447, 1968). TEM taken on 5/9/69 by M. Sage with Philips 300 operating at 60kV. Neg. 3,120X.