DVD quality video of the Contractile Vacuole Complex of Paramecium multimicronucleatum. In vitro CVC rounding/relaxing cycles. An in vitro CV in a ruptured Paramecium cell is surrounded by cytoplasmic vesicles and partially diluted cytoplasmic fluid. The CV periodically rounds and relaxes. One radial arm is visible which can swell as it is still able to accumulate fluid and it then fuses with the CV as the CV relaxes.