Order & Family: Floating unicells or a colony embedded in a matrix;
no differentiation of apical and base structures; only one family.
Genus: Colonies consiting of orderly arranged cells; diameter of cells at transverse section is the same as its length (Illustrations of The Japanese Fresh-water Algae, 1977). Colonies plate-like, cells regularly arranged in a gelatinous matrix; cells spherical or ellipsoid, hemispherical after division (Photomicrographs of the Freshwater Algae, vol. 2, 1984).
Species: Cell body pale blue-green, 3-6 μm in diam. (Photomicrographs of the Freshwater Algae, vol. 2, 1984).
Merismopedia sp.1', x 400, x 640, October 1999, Saitama Pref., by Y. Tsukii
Merismopedia sp.3, x 400, by Y. Tsukii