150 A NATUBALI8T IN CELEBES ch. vi 



respiratory in function, but it is my opinion that the most 

 "widely distributed colours will eventually be proved to be 

 allied to chlorophyl, the green colouring matter of plants, 

 and perform a very similar if not precisely identical 

 physiological function. It is not my purpose to enter here 

 into all the reasons which have led me to this conclusion, 

 although a sketch of the line of argument may be interest- 

 ing to the general reader. The prevailing colour on the 

 coral reefs is a deep greenish-brown colour, and next to that 

 the commonest tint is a bright green. The latter occurs most 

 frequently on young actively growing branches, the former 

 upon the older branches and larger clumps. Some of 

 these colours dissolved in alcohol have been submitted to 

 spectrum analysis by competent authorities, and in many 

 cases the report is that they cannot be distinguished from, 

 or are very closely allied to chlorophyl. If in the future 

 it can be proved, as I believe it will be proved, that a very 

 large majority of the corals on the coral reefs do possess 

 a colouring matter allied to chlorophyl, which performs a 

 physiological function very similar to that performed by the 

 chlorophyl of plants, we shall have an explanation of some 

 of the anomalies of life upon the reefs. 



It is a recognised axiom in biology that all living 

 things are directly or indirectly dependent upon the 

 physiological action of chlorophyl for many of the most 

 important elements of their food, and in accordance with 

 this we find in every locality which supports life, whether 

 it be in rivers, ponds, the sea, the tropics, the deserts or 

 the arctic regions, a fairly even proportion of animals and 

 plants. The one striking exception to this general rule is 

 afforded by the coral reefs where animal life is far in excess 

 of vegetable life. Extraordinarily rich in many forms of 

 animal life, they are exceptionally poor in varieties of sea- 

 weeds and other marine plants. If then it can be shown 



