Reference work entry
Corals are a marine invertebrate Coelenterata. The class Anthozoa includes Rugosa, Heterocorallia, Hexacorallia, Octocorallia and tabulate corals. Coral larvae are originally white and then turn red when the iron in the sea water they absorb is transmitted into the shell. After their death, corals and the sea bed materials transform into fossils through the fossilisation process (Fig. 49).
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