Tetraselmis sp.; a 4-flagellated green algae; lateral view of the cell; together with some crytomonad algae and the diatom Cylindrotheca sp.. Chlorophytes of genus Tetraselmis are also symbionts in the green worm Symsagittifera roscoffensis (Xenacoelomorpha).

The alternating rotation of the cell in clockwise and counter-clockwise dirction raises the question, if and/ or how the beat of the 4 flagella is coordinated. See also a YT-Viedo here by the YT-video here >>>:(1)