Volvox's one of the best-known chlorophytes and's the most developed in a series of genera that form spherical colonies. Each mature Volvox colony's composed of numerous flagellate cells similar to Chlamydomonas, up to 50,000 in total, and embedded in the surface of a hollow sphere or coenobium containing an extracellular matrix The cells swim in a coordinated fashion, with a distinct anterior and posterior poles. The cells have eyespots, more developed near the anterior, which enable the colon… (More on Volvox)