Siderastrea siderea 



lis 189 262 



Fig. 3. A head of Siderastrea siderea was labeled with 14^ by incubation 



with 60uCi Na2H-'-^C03. Pieces were broken from the head at the times 



indicated and their radioactivity and surface area determined (0 0) 



total radioactivity per sq. cm.; (0 0) , radioactivity in an ethanol 



extract. (• •) radioactivity in a 6N-NH4OH extract. Hatched areas 



represent hours of darkness. 



Monastrea annularis 



lie 189 262 



Fig. 4. A head of Monastrea annularis was labeled with 14c by incubation 



with 60uCi Na2H-'-^C03. Pieces were broken from the head at the times 

 indicated and their radioactivity and surface area determined. 



(0 0) , total radioactivity per sq. cm.; (0 ) radioactivity in 



an ethanol extract; (• t) , radioactivity in a 6N-NH4OH extract. 



Hatched areas represent laws of darkness. 



VI-253 



