Rhabdoaskenasia minima is a small (30 x 20 µm) planktonic ciliate commonly found in lakes. This ciliate contains three characteristic ciliary girdles in the anterior half of the cell: one having relatively short cilia, another one with longer cilia that are typically bent posterior and a third girdle with long bristles that faciliate floating in the water. In the next picture, the contractile vacuole can be seen which is responsible for osmotic regulation of the cell (‘blister’-like structure).
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