Polarised light micrograph of Euglena acus and purple bacteria. Euglena is a genus of single celled microorganism which possesses the characteristic features of plants and animals. Euglena acus is needle-shaped, with a rigid cytoskeleton known as a pellicle. It has a flagellum which it is uses for locomotion. A small, single eye spot (red) allows it to move towards light. Purple bacteria are gram-negative proteobacteria that use photosynthesis to produce their own food. Magnification: 372x when printed 10 centimetres wide.