Pandorina

Pandorina 

a genus of mobile, colonial green algae of the order Volvocales. There are two known species, both of which are found in freshwaters. The colonies are globose or elliptic and measure 70–150 microns. They are enclosed in a gelatinous envelope and consist of 16 (less frequently, eight or 32) cells, each bearing two flagella. In asexual reproduction, each cell divides into 16 daughter cells, thus forming a new colony. The sexual process is heterogamy.