Cells are 11 to 18 microns long, not flattened and with two rows of extrusomes located ventrally. The cells are oblong or cylindrical with two flagella inserting subapically. The flagella are thick, longer than the cell, and unequal in length and may coil around the body during swimming. The anterior flagellum is about twice the length of the cell and may coil up during resting, and the posterior flagellum is about three times cell length. The nucleus lies in the middle of the cell. The cells rotate while swimming.