"astrephomene gubernaculifera" is a colonial, flagellated volvocine green algae. it consists of 16, 32, 64 or 128 cells, 2 to 7 of which are small and oriented such that their flagella form a rudder (stein 1958). each cell is surrounded by a gelatinous matrix and contains an eyespot, two flagella and 1-3 contractile vacuoles at the anterior end.