276 THE OCEAN. 



calls himself lord and proprietor of this new crea- 

 tion."* 



The species of Polypes which contribute to the 

 formation of coral structures are very numerous, 

 and differ greatly from each other in the forms of 

 their respective habitations. Some form large round- 

 ed masses, with numerous winding depressions, as 

 the Brainstones (Meandrina); some are studded with 

 holes, filled with thin shelly plates placed perpen- 

 dicularly, and converging to a point in the centre, 

 as Astrcea; some assume the appearance of a mush- 

 room, as Agaricia; but the most general form is 

 that of an irregular, branching shrub. The various 

 kinds are not found scattered indiscriminately over 

 the whole edifice, but each occupying its own zone 

 and position, each performing its own part, assigned 

 by God, in carrying up the wondrous architecture. 

 The principal and most important place is filled by 

 the genus Poriles, which occupies the outside of the 

 reef, at the exposed edge, constructing large rounded 

 masses. The next in importance is the Millepora 

 complanata, which forms thick vertical plates, unit- 

 ing at different angles by their edges, so as to pre- 

 sent the appearance of a honeycomb: the marginal 

 plates only being alive. These two kinds alone 

 are able to endure the intermitting exposure to 

 which the upper edge is subject, in being conti- 

 nually washed over by the surf; other species are 

 found a few fathoms down. Inside the lagoon, 

 there are quite distinct sorts, generally brittle, and 

 thinly branched ; while great round Brainstones 



* Kotzebue's Voyage. 



