Light micrograph of the freshwater alga Volvox globator. Volvox forms large (up to 2mm), spherical colonies with up to several thousand two-flagellated single cells arranged in a regular pattern in the periphery of a colourless jelly. The focus in this picture is on the surface of a colony with the single cells with an amoeboid shape. Culture material of the algae collection at the University of Cologne (CCAC). Microscopic contrast method : Differential interference contrast. Magnification 600x at a print width of 10 cm.