•>., 



fP, 30 



20 



g 10 



J 



HALIMEDA SIMULANS 



N = 65 plonlb/lime penod 



-•- = small initial buds 



o- = exponding but unpigmenled lips 



§ 0800 1600 0000 0800 



1600 



If HALIMEDA 1NCRAS5ATA N -- 30 plants/time period 



uj 40 



s 



UJ 

 en 



S 30 

 uj 



5 20 



Q 

 O 



£ 10 



CO 

 UJ 



I o 



0800 



1600 



0000 0800 



1600 



0000 0800 



1600 



20i 



J 



SAND-PLAIN TRANSPLANTS 



REEF TRANSPLANTS 



N = 15 



N =21 



.. u 



I 



0800 1600 0000 0800 1600 0000 0800 



1200 2000 0400 1200 2000 0400 1200 



TIME OF DAY 



Figure 3. Diel pattern of segment production in Halimeda 



simulans at Coki Point, St. Thomas (top panel) and in ( H. 

 incrassata at Salt River Canyon, St. Croix (middle panel). 

 Solid and dashed lines in the upper graphs were fitted by 

 eye. The histograms (bottom panel) show diel patterns of 

 grazing on branches of H^ incrassata placed on the Salt 

 River Canyou sand plain at a depth of about 24 m or on the 

 reef slope at a depth of 15 m. Error bars show +1 standard 

 error. Shaded bars below the x-axis indicate periods of 

 darkness. 



376 



