The Genus Paramecium is commonly found throughout the world, in fresh and marine water containing bacteria and decaying organic matter. Paramecium is a small unicellular organism. It is elongated and ranges in size from 120 to 300 microns. The outside of the cell is covered with a tough pellicle. Label the pellicle. The posterior half is slightly wider than the anterior half and is bluntly pointed, while the anterior end is rounded. On its underside there is a large and long groove running about half the length of its body. The outer surface of the organism is covered with many hundreds of minute hair-like projections called cilia. Label the cilia.