Fig. 3. Sequence of video frames of a single cell of Lingulodinium polyedrum strain HJ approaching the barrier (dark horizontal line near the bottom). Flow direction is from top to bottom. Frames were taken with an interval of 4 ms; the numbers at the top of each panel show elapsed time in milliseconds. The cell arrived at the barrier at 12 ms and the flash started at 24 ms, resulting in a latency of 12 ms. Scale bar, 50 µm.