20 



b.r all, during the last two months they were in the water, on 

 accovuit of the freshet that had prevailed during that time. These 

 figures agree very closely with those given by Dr. Kellogg for 

 the season before, so that a growth of three inches may be 

 taken as an average year's growth in these waters under favor- 

 able conditions. 



On the reefs in the upper part of the pass, when first visited 

 in the early part of May, 1905, many of the oysters had only re- 

 cently died, as was shown by the presence of the decomposing 

 bodies within the shells. As most of these oysters were known 

 to have settled in the spring and summer of 1903, they were 

 thus not more than two years old at the time of their death, and 

 the length of shells from these reefs will give an idea of the 

 growth during the second season. Many of these shells were 

 measured at different times, and the lengths of ten, representing 

 fairly the usual size, were as follows: 5.75, 6.50, 4.00, 5.25, 6.25, 

 7.00, 4.75, 6.75, 5.50, 3.75 inches. The average length is 5.65 

 inches. The oysters on these reefs had been crowded during 

 their growth, and besides, the ratio between length and width 

 increases with the age of an oyster, so that an oyster grown in a 

 cluster does not have as great a volume as one the same length 

 grown on a flat surface where there is no resistance to its ex- 

 pansion in width as well as in length. 



In order to definitely ascertain the rate of growth of oysters 

 under conditions as similar as possible to those existing on the 

 natural reefs. Dr. Kellogg placed on the Lighthouse Reef a 

 number of cages, made of wire netting, and filled with clean 

 shells. The cage that was left to determine th^ year's growth 

 was placed in position on June 22, 1904. On August 5, 1905,. 

 shells were removed from this cage and the young measured. A 

 number of these shells with spat up to one-half inch in diameter 

 a- the result of not more than six weeks' growth are figured. in 

 Dr, Kellogg 's report. During a heavy storm in February i5? 

 1905 this cage was washed away from its former location on the 

 reef, and all attempts to find it during the spring of 1905 were- 

 fruitless. While tonging on the outer, deep portion of this 

 reef March 23, 1906, this cage was brought up. Although the 



