This beauty is called Stentor coeruleus and is among the most admired and popular ciliate around. They measure around 1 mm, which makes it possible to observe them with naked eyes and they possess a blue-green pigment named stentorin. Stentorin plays a major role in light detection and defence mechanisms. When Stentor is being threatened by a predator, the toxin from the stentorin pigment granules are released in the environment, which cause the predator to retreat and gives a chance for S. coeruleus to escape! 

The oral aperture is spiral-shaped and has thousands of small specialized cilia, which move together to create a vortex that captures food particles, bringing them directly to the mouth. These particles will then get digested in special structures called food vacuoles, which are full of digestive enzymes. They’re basically primitive stomachs! You can see some small green dots inside the Stentor which are some algae trapped in those food vacuoles and are being digested.

The macro nucleus appears as small white bubbles linked together resembling beads on a string. This macro nucleus contains DNA that is necessary for reproduction and regeneration. The bigger this unicellular organism is, the more copies of its whole genome it has. That way it can regenerate from small pieces when it gets damaged. Only a small piece of DNA is necessary to form a whole new Stentor!