is a very large ciliate measuring from 500-2000 microns long when
extended. There are a variety of species of Stentor.
coeruleus is a very large trumpet shaped, blue to blue-green ciliate
with a macronucleus that looks like a string of beads (dark connected dots
on the left). With many myonemes, it can contract into a ball.
It may also swim freely both extended or contracted.
stentor uses the cilia to sweep food down into its gullet.
polymorphus is 500-1500um long and hosts many Zoochlorellae which
makes this species green. The Zoochlorella live in symbiosis with
are always fun to watch and are available from science supply
companies. Some instructors do not have luck keeping their cultures
Stentor shown at lower left is Stentor coeruleus or Stentor
polymorphus. The image was taken with a phase contrast
microscope. Notice the macronucleus (round circles that look like a string
Video of a Stentor captured with a microscope courtesy of James Tripp.