Coral and Coral Reefs

An account explains the structure and origin of corals and coral reefs, distinguishing the ornamental red coral from the more widespread white coral and showing that both are hard skeletons produced by simple polyp animals. It describes polyp anatomy—cylindrical bodies with a mouth ringed by tentacles—and feeding behavior, and details modes of reproduction including fission, budding, and free-swimming larval stages with cilia that enable dispersal. The narrative explains how polyps secrete calcium carbonate from seawater to build internal skeletons, how connected colonies function cooperatively, and how the accumulation and growth of these skeletons produce extensive reef structures over time.