Genus: Unicellular; planktonic; cell body elongated cylindroid, curved or twisted; both ends rounded, with spiny projections; cell wall not separated into two parts (compare to Centritractus); several chloroplasts plate-like, without pyrenoids (Guide book to the "Photomicrographs of the Freshwater Algae", 1998). Species: Cell body cylindrical, curved, without projections at both ends, 5-6 μm in diam., 50-100 μm long (Illustrations of Japanese fresh-water algae, 1977).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Azami-ike (pond), Norikura highland, Azumi, Matsumoto city (formerly Azumi village), Nagano Pref., Japan, June 8, 2006 by Y. Tsukii