The Suctoria.

The fully developed suctorians have no cilia, but instead have numerous long contractile tubular tentacles with which they capture prey organisms and suck out their body contents.

They are grouped with the ciliates on account of having a ciliated larval stage, and because they possess both a macronucleus and a micronucleus, in common with all other ciliates. They reproduce in some cases by binary fission, but more often by a process of budding in which ciliated motile larvae are formed either from the upper surface of the adult organism, or from a kind of brood chamber within the body of the cell. The larvae attatch themselves in a new location, lose their cilia, and develop tentacles. Suctorians are also known to conjugate.

They are fairly common in most freshwater habitats, feeding mainly on other ciliates.

  Acineta and Podophyra.

Acineta and Podophyra are two of the most commonly encountered suctorians.