Species: Colonies forming a slightly curved square or rhomboid, up to 65-90 μm in width; cell body up to 18-20 μm in diam. (Photomicrographs of the Freshwater Algae, vol. 2, 1984).

31 μm 63 μm 94 μm; x 640

Gonium pectorale Müller, stock Sfum-81, axenic culture with KCM & Hyponex (December 23, 2003 to January 14,2004), cell body nearly spherical, 13-14 μm in diam., x 640, near Yanase river, Mizuko, Fujimi city, Saitama Pref., Japan, December 28, 2003 by Y. Tsukii

Gonium pectorale Müller, stock Sfum-83, axenic culture with KCM & Hyponex (December 23, 2003 to January 14,2004), cell body nearly spherical, 11-12 μm in diam., x 640, near Yanase river, Mizuko, Fujimi city, Saitama Pref., Japan, December 28, 2003 by Y. Tsukii