Family [Gonatozygaceae]:
Cell body cylindrical, slightly swelled at both ends, loosely attached with each other to form a filament;
cell wall consists of a single partition, two layers, with small pores, covered with dots, granules or
short spines; chloroplast ribbon-like, with many aligned pyrenoids.
Genus:
Chloroplasts plate-like or slightly spiralled, centrally placed
(Illustrations of The Japanese Fresh-water Algae, 1977).
* Gonatozygon pilosum var. echinatum Krieger: cell body cylindrical 96-140 μm long, 5-(5.5-7.5) μm wide, L/W = 15-20, cell wall covered with many fine hairs, both ends slightly swelled (Illustrations of The Japanese Fresh-water Algae, 1977).
Gonatozygon pilosum Wolle var. pilosum: cell body cylindrical 177-(180)-300 μm long, 10.5-15-(15.5) μm wide, L/W = 12-20, cell wall covered with many hairly spines, both ends slightly swelled (Illustrations of The Japanese Fresh-water Algae, 1977).
Gonatozygon monotaenium De Bary: cell body cylindrical (74-145)-284 μm long, 7.5-(9)-11.5 μm wide, L/W = 10-25, cell wall with many granules, both ends slightly swelled (Illustrations of The Japanese Fresh-water Algae, 1977).