a colonial peritrich similar to Zoothamnium
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
whose stalks are described as contracting in a zig-zag fashion. Pseudocarchesium
also has discontinuous myonemes. From a freshwater pond near Boise, Idaho. Brightfield.