Living observations on Sonderia vorax : some morphological characters. A. Cell view from the right side of oral opening. B. Cell view from the left side of oral opening. C. Extruding longer type extrusomes. D. Anterior part of the cell with a number of resting longer type extrusomes. E. Resting longer type extrusomes at higher magnification. F. Nuclear apparatus after Feulgen staining. Abbreviations: exI, longer type extrusomes; lol, lower oral lip; ma, macronucleus; mi, micronucleus; uol, upper oral lip. Scale bars = 20 μm (A, B), 10 μm (C, E, F), 15 μm (D).