88 



CORALS AND CORAL ISLANDS. 



cretes the axis within, it gives out buds externally ; thus the 

 branch rises. New branches commence at intervals over the 

 sides of the rising stem or branch through the starting of new 







ISIS HTPPUTCTS. 



budding centres, and so, finally, the Gorgonia zoophyte is 

 completed. 



In a few species, the axis is partly or wholly calcareous. 

 In the Isis family, it is made up of a series of nodes and 

 internodes. The former, in the genus Isis, are white, calcare 

 ous, furrowed or fluted pieces ; and the latter are smaller and 

 horn-like in nature, as illustrated in the preceding figures. 

 In the branching stem here figured, the main stem and the 

 branch on the left are simply the axis, bare of the polyp-layer 



