Carchesium a colonial peritrich similar to Zoothamnium but Carchesium is distinguished by zooids with discontinuous myonemes allowing individuals of the branched colony to contract independently. However, as seen in this image, the entire colony may contract simultaneously. The stalk of Carchesium contracts in a spiral configuration, seen in this image, unlike Zoothamnium and Pseudocarchesium whose stalks are described as contracting in a zig-zag fashion. Pseudocarchesium also has discontinuous myonemes. From a freshwater pond near Boise, Idaho. Brightfield. This image was taken by William Bourland. He now uses a Zeiss Axioskop 2 with Spot Insight and Spot Flex CCD cameras (Diagnostic Instruments). Image copyright: William Bourland, image used under license to MBL (micro*scope).
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Freshwater and Terrestrial Microbes of Idaho (USA) and Elsewhere
|Description of Carchesium: Genus of sessile peritrich ciliates, forms tree-like colonies which can reach 4mm in height. There may be over one hundred bell-shaped cells (zooids) supported by branches of the stalk, each of which has a separate contractile myoneme and is capable of independent contraction. Typical peritrichous oral ciliature consisting of anticlockwise spiraling kineties at the anterior end of the cell. Somatic ciliature is absent, typical of the order Peritrichida. Usually there is a ribbon-like macronucleus. Habitat and distribution: freshwater and marine, often found as ectocommensals on aquatic organisms. Common. |