Volvox green algae, light microscopy footage. Spherical colonies of Volvox green algae. Each colony is a hollow sphere made up from thousands of cells connected by cytoplasmic threads and arranged in a single layer. Each cell has two flagella, which point outwards, and are used for locomotion. The spheres (lighter green) within each colony are daughter colonies, which are produced asexually. This sample was obtained on Dowrog Common, a Site of Special Scientific Interest (SSSI) in Pembrokeshire, South Wales.