Colacium (coal-ace-ee-um) is a euglenid flagellate in which the cells are attached to the substrate b y means of a mucoid stalk. the euglenids are attached to the stalks by their anterior region. As in this species, the stalks may branch and form moderately large aggregates. The individual cells may break free from the stalks and swim away, at which time they are indistinguishable from members of the genus Euglena. Phase contrast. This picture was taken by David Patterson and Mark Farmer of material from freshwater sites in the vicinity of the University of Georgia in Athens, Georgia, USA) in April, 2001 and from collections of organisms maintained at the University. Image copyright: D. J. Patterson and Mark Farmer, image used under license to MBL (micro*scope).
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From the collection
Athens, Georgia, USA
|Description of Colacium: Euglenids; with plastids, normally attached by mucilaginous secretions from the canal; cell division occurs to produce bunches, sheets or dendroid colonies of a few to hundreds of cells with thin sheaths, joined together by mucilaginous stalks; settled cells shed the locomotory flagellum but retain the basal portions of their 2 flagella within the reservoir, including the (reduced) flagellar swelling; any cell can regrow the long flagellum, escape from the colony as a free-swimming organism (indistinguishable from Euglena), settle elsewhere and secrete a new stalk and sheath of mucilage; eyespot and flagellar swelling present; plastic, euglenoid movement only slight in colonial state; not flattened; canal opening subapical; freshwater, attached to filamentous algae, aquatic angiosperms, Cyclops, Daphnia and other aquatic animals, including fish; fairly common, worldwide. Type species: C. vesiculosum, Ehrenberg, 1833. |