WikipediaRead full entry The Volvocaceae are a family of
unicellular or colonial biflagellates, including the typical
genus Volvox. The family was named by Ehrenberg in 1834, and is
known in older classifications as the Volvocidae. The simplest
of the Volvocaeans are ordered assemblies of cells, each similar
to the related unicellar protist Chlamydomonas and embedded in a
gelatinous matrix. In the genus Gonium, for example, each
individual organism is a flat plate consisting of 4 to 16
separate cells, each with two flagella. Similarly, the genera
Eudorina and Pandorina form hollow spheres, the former
consisting of 16 cells, the latter of 32 to 64 cells. In these
genera each cell can reproduce a new organism by mitosis. Other
genera of Volvocaceans represent another principle of biological
development as each organism develops differented cell types. In
Pleodorina and Volvox, most cells are somatic and only a few are
reproductive. In Pleodorina californica a colony normally has
either 128 or 64 cells, of which