Portrait (right side) of the small Odontostome ciliate, Mylestoma anatinum
. The cell is colorless with a laterally compressed rigid transparent pellicle typical of Odontostomes. The outline is roughly discoid with the dorsal convexity ending in a sharp anterior beak. The posterior is broadly rounded without spinous projections. The cytostome is located in a posterior depression (not seen in this image). Somatic ciliature is strongly reduced to two long posterior cirri, an adoral zone of membranelles and a small perizonal complex anterior to the cytostome. There is a single posterior contractile vacuole and a single macronucleus. Refractile brownish granules are seen scattered through the cytoplasm. Collected from bottom sediments of a freshwater aquaculture tank near Boise, Idaho December 2003. DIC optics.