Early interest in cell division was fueled by recognition of its importance in both the development and maintenance of animal form and by the relatively simple and easy measures that enabled 19th-century biologists to witness its dynamic events. The realization that those events were clearly organized and controlled by each individual cell added to the attraction. In their thinking about cell division, biologists have tried to formulate a basic or fundamental form of the process that can, with minor adjustments, be used to explain the ways in which it occurs in all its variations. For reasons of convenience and history, the basic form of cytokinesis starts with a spherical cell containing a central mitotic apparatus.