A genus of organisms belonging to the kingdom Protista, phylum Ciliophora -- the ciliates. They are single-celled, slipper-shaped and covered with cilia, which they use to move. They can move very fast. Other features of members of genus Paramecium include contractile and food vacuoles, a mouth near the center, and a pellicle covering the outer surface which helps it hold its slipper-shape. Paramecium is often studied in high school and college biology classes.