DEPARTMENT OF MARINE BIOLOGY. 



143 



Thirteen of the tiles to which planulse had attached themselves were placed 

 in this car on June 10. Dr. Mayer examined them on July 14 and forwarded 

 the notes appearing in the fourth column of the following table. 



Record of Tiles placed in Live-car anchored off Loggerhead Key. 



* The Roman numerals refer to the parent colonies. 



Dr. Mayer did not specifically report in his notes of July 14 on five of the 

 tiles. These five include the four bearing young Porites clavaria and one 

 bearing young Agaricia crassa. He says regarding them, "The five other 

 tiles have only a few small corals on them." As the young polyps of Porites 

 clavaria are so small that they can be seen with the naked eye only with diffi- 

 culty and may easily be overlooked even with a reading-glass, and as there 

 were originally only three polyps of Agaricia, Dr. Mayer's report is highly 

 gratifying. But the outcome of the experiment is not yet known. 



In order to check the favorableness or unfavorableness of the environment 

 in a floating live-car for the life of the species of corals represented by the 

 attached young in the live-car, 3 specimens of Favia fragum, 4 of Agaricia 

 crassa, 1 of Porites clavaria, and 2 of Porites astreoides were taken from 

 the reef whence the parent colonies came and were cemented to two tiles, 

 which were also placed in the live-car alongside the young corals. Dr. 

 Mayer reported on these specimens on July 14, that 2 colonies of Agaricia 

 were about half dead ; i Favia was dead, but the other 2 were thriving ; the 

 Porites were doing well, except a patch on one of the P. astreoides colonies. 



The 8 other tiles were planted on iron stakes along the outer face of the 

 northwest side of the Fort Jefferson moat wall, in water ranging at extreme 

 low tide from 12 to 18 inches in depth. Only Porites astreoides is repre- 

 sented ; 5 tiles bore the offspring of colony I, 22 young polyps, while 3 tiles 

 bore the offspring of colony II, 21 young polyps. 



A comparison of the number of attached young obtained from the different 

 parents which gave out planulae brings out interesting data showing the rela- 

 tive mortality of different stocks. 



Number of attached Young obtained from the Different Parent Colonics. 



