Single sphere, often thick-walled. Pores more or less regular, circular, or irregular, of variable shape and size, with or without polygonal frames, with or without thin, bristle-shaped by-spines or thorns. No primary (conspicuously larger) radial spines. Highly variable group with many different morphotypes present chiefly in middle and high latitudes (e.g., Cenosphaera cristata Haeckel in Antarctic waters, cf. Petrushevskaya, 1967; Cenosphaera compacta Haeckel and Cenosphaera elysia Haeckel in subantarctic-transitional areas, cf. Boltovskoy and Riedel, 1980). Shell diameter: 50-320 µm.
Ref.: Petrushevskaya (1967), Boltovskoy and Riedel (1980).