EARLY LIFE-HISTORY OF CORALS 67 



These symbiotic algse are crowded most densely about the 

 region of the month, which is in consequence more deeply 

 coloured, but, strangely enough, after the larvte have lived 

 their independent existence for some time, and have become 

 possessed of a definite stomodeum and internal cavity, these 



Fig. 10. 



A Section through a Commicmcixg Colony of 

 Ccenopsammia nigrescens, 



Showing the production of daughter zooids by budding from 

 the sides of the parent. 



Zooanthellse are passed out through the mouth and into the 

 water. 



Although it has been said that the larva becomes fixed 

 after a few days passed as an active, free-swimming creature, 

 still, among those that have been watched in aquaria a great 

 majority display a singular reluctance to settling down : among 

 Wilson's larvae of Maniciana many did not settle down until 

 they had spent three weeks swimming free, and Duerden 

 came to the conclusion that if fixation did not take place 

 within the first few days, it did not occur at all, a though the 

 larvge continued to swim slowly about the vessell, and even 



