Stentor coeruleus. Light microscope footage of Stentor coeruleus, a large ciliate found in lakes, ponds and streams throughout much of the world. It can reach a length of up to 2 millimetres. Cilia can be seen lining the peristome, a rim around the oral area. Their rhythmic beating draws bacteria and other organisms into the cytostome or mouth (darker area). The macronucleus appears as a beaded chain. Filmed with brightfield illumination.