Light micrograph of the freshwater eye flagellate Phacus sp. Phacus belongs to the class Euglenophyceae and forms large, mostly flattened cells with a rigid shell. At the front end of the cell there is a swimming flagellum and usually a red eye spot. The cells have a large nucleus, many chloroplasts without pyrenoids and paramylon granules as reserve material. The cell shown here has a particularly large paramylon grain in the posterior end of the cell. Microscopic contrast method : Differential interference contrast. Magnification 500x at a print width of 10 cm.