DEPARTMENT OF MARINE BIOLOGY. 



141 



Considerable information has been procured on the habitat of the corals 

 inhabiting the moat, but it is not in condition for presentation. One growth- 

 record is interesting. In 1908 no specimen of Oculina growing naturally in 

 the moat was observed ; but in 1909 two rather large colonies were discovered 

 in a conspicuous place examined in 1908. If these colonies were there in 

 1908, they were probably small. They were measured on May 15, and, after 

 my departure from the Tortugas, were again measured by Dr. Mayer on 

 July 13. The amount of growth in millimeters is given below. 



♦Excepting the increase in height the same as on May 15. 



Rate of Growth. 



In 1908 a series of measurements was initiated to determine the rate of 

 growth of corals, and the results at the end of the first year are given in the 



Table showing Rate of Growth. 



1 Range of branches. 



■Tallest branch. 



3 Diameter of cluster. 



