Pandorina

Pandorina is a genus of green alga composed of 8, 16, or sometimes 32 cells, held together at their bases to form a globular colony surrounded by mucilage. The cells are ovoid or slightly narrowed at one end to appear keystone- or pear-shaped. Each cell has two flagella with two contractile vacuoles at their base, an eyespot, and a large cup-shaped chloroplast with at least one pyrenoid.

The colonies coordinate their flagellar movement to create a rolling, swimming motion. Pandorina shows the beginnings of the colony polarity and differentiation seen in Volvox since the anterior cells have larger eyespots. Molecular sequencing has shown that pandorina is monophyletic.