132 CORAL AND ATOLLS 



but it is tlie natural instinct of the collector to pick out well- 

 marked and well-grown forms as his specimens. 



Fig. 46. 



The "Stings" caused by Contact with a Colony of 

 Millepora alcicorn'is. 



In 1898, Professor Sydney Hickson made an exhaustive 

 study of the so-called species of the hydrocoralline Milleporce, 

 and he came to the conclusion that there were " very strong 



