Volvox is a genus of freshwater green algae. Free-swimming cells join together – up to 50,000 strong – to create colonies that are gelatinous hollow spheres formed by collective secretions.
Each cell sends out 6 fine fibrils. The fibrils connect with different neighboring cells, creating a communication network.
Volvox cells coordinate to swim in unison. While single cells have some individuality, they work together for the good of the colony.
The colonial sphere develops cellular specialization, including distinct anterior and posterior poles. Eyespots become more developed in the front (anterior), better allowing a colony to swim toward the light. Encountered encumbrances are sensed and swum around.