SOME PROBLEMS OF THE SEA. 19 



of a fish that has been caught. But that is only one half 

 of the story — the nitrogen need not leave the sea, but 

 may go on its beneficent course through a perpetual series 

 of recurring cycles, which render possible the life and 

 growth of successive generations of organisms. Then, 

 again, another great series of the changes in the sea which 

 we wish to designate must be regarded as constantly 

 circulating within the sea, from the body of an organism 

 to a dead deposit, then, it may be, passing into solution, 

 and once more — perhaps after intermediate stages — 

 becoming part of a living body again. The carbonate of 

 lime in Corals, Foraminifera and Shells, and the silica in 

 Sponges, Radiolaria and Diatoms is an example of such 

 a series of phenomena, and cyclical change or circulation 

 of matter is the English term which best expresses the 

 facts of the case. If we must have a technical term in 

 classical form I would propose " hylokinesis "* as being 

 more comprehensive and appropriate than metabolism. 



It seems possible to obtain a good deal of interesting 

 information in regard to the hylokinesis of the sea 

 without attempting a numerical accuracy which is not 

 yet attainable. The details of measurement and com- 

 putation become useless, and the exact figures are non- 

 significant, if the hauls upon which they are based are not 

 really comparable with one another and the samples 

 obtained are not adequately representative of nature. 



I wish now in a third, and concluding, section of this 

 address to bring before you a problem in geographical 

 distribution in which I have lately been much interested. 

 In bringing to a conclusion my Report upon the Ceylon 

 Pearl Fisheries I had to summarise the faunistic 

 relations of the Grulf of Manaar, and it naturally occurred 



* Kindly suggested to me by my colleague Prof. H. A. Strong 



