EARLY LIFE-HISTORY OF CORALS 59 



growing on trees. As only the stony colonies are of any 

 importance as reef-builders, they alone will be discussed. It 

 must not be imagined that the hard corals are dead things, or 

 that a great stony boulder of Poritcs is merely a mausoleum 

 upon whose surface life is flourishing. The coral that we are 

 accustomed to see in its dried and bleached form is only the 

 skeleton of a colony of zooids, each of which has its separate 

 parts, although it is only a member of a great compound 

 body. 



All corals do not live in colonies, and many species of 

 solitary corals are to be found about a reef. The comparison 

 of a living solitary coral with the skeleton that remains after 

 it is dead will give the best idea of the true nature of the 

 specimens called " corals " in museums. The individual coral 

 zooid is most like a common sea-anemone, and if an anemone 

 be imagined to develop a calcareous skeleton, this skeleton 

 would be very much like what remains when a solitary coral 

 is dried and bleached. 



A vast aggregation of these skeletons, all very minute and 

 all joined together in the form of a boulder, or a branching 

 growth, constitutes what we know as " coral." There are 

 many problems connected with the production of this " coral " 

 and with the life-histories of the corals themselves, but of a 

 great many of the most important details knowledge is 

 strangely lacking. 



How far all the myriad forms to be found upon a reef are 

 to be considered as separate species, or only as mere varieties, 

 is a point still open to debate ; and a vast amount of work 

 remains to be done before the question may be definitely 

 settled. 



The methods of feeding, of growing, and of reproducing — 

 in fact all the life-functions of the corals — are but very little 

 understood, for corals are usually studied when dead and 

 dried in museums. It is for this reason that any work done 

 actually upon a living reef is likely to help in the solution of 

 vexed questions, for no real knowledge of corals is likely to 

 come from the study of their dead remains, when far removed 



