Polytomella (paul-ee-toe-mell-a) is one of a small number of green (Viridaeplantae) algal genera which lack plastids. There are four flagella inserting in a square pattern - and only two opposed flagella can be seen in this image. The flagella insert in small dimples at the anterior end of the cell. Often found in habitats rich in organic matter and low in oxygen. Phase contrast.