A PRACTICAL METHOD OF SPONGE CULTURE. 577 
least once after having lain for an unknown time on the bottom vegetation 
under conditions which other experiments have shown to be inimical, and a 
considerable proportion of the deaths occurred at those times. Had the wires 
remained intact and the cuttings been kept always suspended above the vegeta- 
tion the death rate at the end of three years would undoubtedly have been 
Per 
cent. 
40 
20 
Biscayne Bay. 
Biscayne Bay. 
20 
Sugar Loaf Key. 
eer after planting_- 10 20 30 40 50 60 
Fic. 7.—Percentages of mortality among different lots of sponges grown from cuttings at Sugar Loaf Key and 
Biscayne Bay. 
under 10 per cent. Curves showing the percentage of mortality among different 
lots of sponges at Sugar Loaf Key and Biscayne Bay are shown in figure 7. 
These sponges were all on wires suspended above the bottom. 
At Anclote Key, owing to the almost constant turbidity of the water, it 
has been found impossible to determine the mortality among sponges planted 
on the bottom. At Cape Florida, in order to obtain data on this point and to 
B. B. F. 1908—37 
