Polarised light micrograph of Pseudovorticella sp. ciliates and Anabaena sp. cyanobacteria. Pseudovorticella is a filter-feeding freshwater protozoan with a bell-shaped head and a contractile stalk that is anchored to a substrate. Cyanobacteria are bacteria that obtain their energy through photosynthesis. Magnification: x550 when printed at 10cm wide.