Paramecium
From Freepedia
- For the musical band with a similar name, see Paramaecium.
| Paramecium | ||||||||||||
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| Image:Paramecium.jpg Paramecium aurelia | ||||||||||||
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Paramecium is a well-known genus of ciliate protozoa, commonly studied as a representative of that group. The cells are slipper-shaped, and range from 50 to 300 μm in length, depending on species. Simple cilia cover the body, and there is a deep oral groove, containing inconspicuous compound oral cilia, as found in other peniculids. Osmoregulation is carried out by a pair of contractile vacuoles, which actively expel water absorbed by osmosis from the surroundings. Paramecia are widespread in freshwater environments, and are especially common in scums.
The division into species is still in flux — for instance, P. aurelia has recently been divided into 14 species — but the following are representative:
- P. aurelia Ehrenberg, 1838
- P. bursaria (Ehrenberg) Focker, 1836
- P. calkinsi Woodruff, 1921
- P. caudatum Ehrenberg, 1838
- P. duboscqui Chatton and Brachon, 1933
- P. jenningsi Diller & Earl, 1958
- P. multimicronucleatum Powers & Mitchell, 1910
- P. nephridiatum von Gelei, 1925
- P. polycaryum Woodruff, 1923
- P. putrinum Claparede & Lachmann, 1858
- P. trichium Stokes, 1885
- P. woodruffi Wenrich, 1928
A number of doubtful species have also been recorded.
