CORAL BUILDERS. 



235 



ever, does take place at length, preparatory to the 

 formation by each of its own elongating disk and 

 line of new mouths. This serves to explain the 



FIG. 50. BRAIN CORAL (Meandrina cerebriformis}. 



sinuous furrows on the surface of the corallum of the 

 Brain corals (fig. 50). 



The only other important group of coral animals 

 to which it will be necessary to allude, are the Hy- 



