Cell bodies attached to substrate by stalk or “stem”.
The cup-shaped cell body has a crown of cilia used for food capture. This ciliated crown can be withdrawn. The surfaces of the cell bodies are ornamented.
Disturbance (here the vibration of the camera shutter) causes the stalk to coil up rapidly, then slowly extend again afterwards. The movement is mediated by a calcium-binding protein called spasmin (see Misra et al. 2010 Biophysical Journal 98 (12): 2923-2932 Pubmed).
The pictures above show different species, some larger and some smaller.
Note the spiraling of the spasmin filament within a tubular housing (above).
The beating of Vorticella cilia sets up a revolving current around the cell body, as shown in this video:
Opening to oral cavity covered by a cap-like structure which bears the peritrichous cilia. I noticed that the fluid flow around the ciliate was accompanied by a beating motion inside the oral cavity, but I’m not sure if that was the cause of fluid flow or whether it was a feeding motion.
Sessile ciliate encased in a vase-shaped lorica (shell) that is also provided with a lid, which the cell can shut behind itself after it retracts into the lorica. The anterior part of the cell has a crown of beating cilia used to draw food into the mouth. A contractile vacuole is visible just beneath the crown.
The empty loricae of dead ciliates may be confused with the empty tests of dead testate amoebae:
The following sequence of images illustrates the unfurling of a Thuricola from a retreated position:
Watch the streaming of particles past the feeding cell in this video:
Sessile ciliate with a vase-shaped lorica (test), without a stalk or lid.