A family of green algae in the order Chlorococcales. Colonial algae usually arranged 3 dimensionally in spherical to loosely spherical shapes. Individual cells connected to each other via cell wall extensions. Cells usually in an even number arrangement. Chloroplasts plate-like with 1 pyrenoid. Name derrived from coelom, in reference to the cavity created inside the sphere. Nonmotile.
Species in this family include: