TWO-LAYERED ANIMALS— PHYLUM COELENTERATA 



131 



masses mentioned have been produced. The South Pacific waters are 

 dotted with many thousands of coral islands, and the coral reefs that lie 

 just under the surface of the water are a great hazard to ships traveling 



Photos by Winchester 



Fig. 9.10. Varieties of coral. The coral polyps are quite varied in their methods 

 of depositing their limestone coverings, giving many interesting and beautiful forms of 

 coral deposits. From left to right and top to bottom these are : Star coral, Pacillopora 

 grandis ; finger-like madrepore, Madrepore digitata ; Brain coral, Meandrina sinuosa ; 

 mushroom coral, Fungia dentata ; staghorn coral, Madrepore cervicornis ; and precious 



red coral, Corallium rubrum. 



