Ciliates
Bell animalcules
Vorticella and other peritrichs
Little upside-down bells on threads. The stalk coils like a spring and snaps the bell back when anything disturbs it.
What to look for
- Bell-shaped cell with a lip of cilia that draws a current toward the mouth.
- A single, unbranched stalk with a contractile thread inside: Vorticella. Branched colonies: Carchesium, Zoothamnium (contract) or Epistylis (does not contract).
- Often in clusters on plants, debris, even on the shells of small crustaceans.
Size in the field
Each bell is small: at 100× a group looks like a cluster of tiny dots on threads; use 400× for detail.
Where to find it
Almost anywhere with organic matter: plant stems, decaying leaves, the sides of aquaria and culture jars.
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