PREFACE 



When a naturalist has the good fortune to spend a few 

 weeks or months within easy reach of a tropical coral reef 

 he gains an impression of animal and vegetable life which 

 he can never forget. It may be that his aesthetic sense is, 

 at first, stimulated and charmed by the beauty of shape and 

 colour that he sees, but his more permanent interest becomes 

 diverted to the intricate correlations of the multitude of 

 living organisms and the infinite variety of their form and 

 structure. 



From the time of such an experience everything which is 

 brought to him from a coral reef by friends and seamen is 

 not only an object of interest, but often brings with it a 

 thrill of reminiscent pleasure. It is difiicult for him to 

 shake off, if he desired to do so, the fascination of the corals. 



Since my visit to the coral reefs of North Celebes many 

 years ago I have received from several friends specimens 

 from the shores which they have explored, not only the hard 

 stony things called corals, but soft glutinous things, animal 

 and vegetable, fish, and some worms and sponges. I wish 

 I could find time and patience to describe the many points 

 of interest in all these things, but I must confine myself 

 within certain Hmits, and these must be the boundaries, 

 wide as they are, of my own conception of the meaning of the 

 word " coral." But if I write about corals I cannot hmit 

 myself to those of the coral reefs, for such things are not 

 restricted, as many may suppose, to the warm tropical seas 

 but are, as will be seen in the text, world-wide in their 

 distribution. 



The immense numbers of genera and species of recent 



