Fig. 2. Consecutive video images of the contractile vacuole in a mechanically compressed cell of Paramecium multimicronucleatum. The number at the upper left corner of each frame corresponds to the time (s) when the picture was taken. Time 0 corresponds to the beginning of the series. CV, contractile vacuole; RA, radial arm. Asterisks show swollen portions of the radial arms. The radial arms become thinner after reattachment to the CV. See text for details. Scale bar, 10 µm.