AMERICAN FISHERIES SOCIETY. 



the water was remarkably uniform ; the greatest specific gravity- 

 being 1,020 and the least 1,018, an'd the temperature of the water 

 in the tank was at all times below that of the pond, in which the 

 sun shone directly. We made no attempt to estimate the num- 

 ber of these minute eggs, which are only visible under the 

 microscope, but took all we could get from the four b\ishels of 

 oysters. 



The bottom of the large pond was covered with scollop shells; 

 stakes were driven about twenty feet apart all over its bottom 

 and strings were stretched between these, while on the strings 

 we hung perforated shells. We obtained a good " set " of oysters 

 in this pond, the best on the shells at the bottom, and, while 

 there was six feet of water in the center of the pond, we obtain- 

 ed no "set" whatever on the suspended shells beyond three feet 

 from the bottom. At three feet we noticed an occasional oyster, 

 within two feet of the bottom they were more plentiful, and in- 

 creased as the bottom was approached. On September 19th, we 

 drew off the pond and examined it for the last time before 

 winter; there were thousands of young oysters of the size of a 

 dime. 



Prof. John A. Ryder, of the U. S. Fish Commission, has sug- 

 gested an admirable way to collect spat, by means of a canal 

 provided with ledges near the top to support receptacles for the 

 cultch. These receptacles are formed by wooden strips and 

 wire cloth, and hold about three bushels of shells each, the 

 "basket" being three feet wide, three feet deep, and only six 

 inches thick, so that the shells are thickly presented to the float- 

 ing spat. The experiments of Prof. Ryder, have been very 

 valuable, and so have those of Prof. Brooks, Lieut. Winslow, 

 Prof. Rice and Col. McDonald in America, and those of Profs. 

 Hock, Horst and Mobius, and M. Bouchon Brandeley in Europe. 

 Prof. Ryder lays down the following principles: 



1. "Oyster embryos under ordinary conditions in open water, 

 diffuse and affix themselves throughout the three dimensions of 

 such a body of sea water. This is a well-known and readily 

 verifiable fact. 



2. " The fry will adhere to smooth surfaces as well as to 

 rough ones. 



