Eutetramorus

Eutetramorus is a genus of algae belonging to the family Radiococcaceae. It is planktonic in freshwater habitats; it has been reported from Europe and North America. Eutetramorus consists of microscopic colonies of cells embedded in a structureless mucilage. The cells are spherical, with cells often in sub-groups of four or eight. Each cell contains a single nucleus and one parietal chloroplast with one or more pyrenoids. Asexual reproduction occurs via the formation of four or eight (occasionally 16) spherical to ovoid autospores; they are released when the mother cell wall gelatinizes. Sexual reproduction and flagellated life stages have not been observed....read more on Wikipedia.