The image at the top of this page shows a typical view of a Stentor using bright field illumination. When attached to a substrate, the Stentor has a trumpet shape. Any disturbance makes the whole body contract to become a blob of protoplasm. The image to the left shows Stentor when swimming where it adopts an oval or pear shape. To find new feeding grounds, the animal swims by means of cilia that cover the body.
Stentor can be very colourful - there are green, blue and amethyst coloured species.
The figure on the left shows a green form using dark field illumination. The green colour is a result of the microscopic green algae which Stentor ingests. The algae live in symbiosis with the Stentor, ie the algae and Stentor mutually benefit from the close association. The algae uses photosynthesis to convert Stentor's waste products to useful nutrients. Observing features using phase contrast To observe the cilia of Stentor, a special type of illumination called phase contrast can be very useful.