Answer: Alexandrium catenella is a species of dinoflagellates. Alexandrium has two flagella that enable it to swim. While one flagellum encircles the cell causing the cell to rotate and move forward, the other extends behind the cell and controls the direction.
The cell wall is composed of cellulose Theca.
Length 20 - 48 μm, width 18 - 34 μm
Yellow-green to orange-brown
Forms chains of 2, 4 or 8 cells
