VENUS MERCENARIA 23 



The beds in this experiment were planted with the fear that the 

 clams would wander. The result, however, showed conclusively 

 that they do not have this habit — or that they did not exhibit it 

 in this particular case. The clams were found where they were 

 placed within the limits of the original beds. Careful digging 

 around the margins of the beds failed in every instance to show 

 any wandering tendencies. 



Growth under wire netting 



In order to be perfectly certain that clams should have no means 

 of escape, three cages of wire netting were constructed, bounding 

 the margins of the area containing clams in each case to a depth 

 of 5 inches and covering the top. These forms never burrow to 

 a greater depth than this, and there was no possibility of escape. 

 In each case the netting remained intact, and certainly was not 

 disturbed. These beds were exposed only during the full moon 

 tides. Here also the seaweed seemed to play an important part 

 in the results. In one case the netting was sunk so deep as to be 

 covered with sand, and consequently no seaweed attached, as it 

 did on the other cages. Growth was much more rapid here, 

 though the clams in this bed were smaller when planted, and, as a 

 consequence, a more rapid growth should have been expected. 



The results were as follows: 



Cage 1 Clams planted July 6, i T \ inches long. Some seaweed 

 was attached to the wire of the cage. The clams were removed 

 Dec. 30. The increase in volume was 145$. 



Cage 2 Planted July 6, i T 6 ^ inches in length. Removed Dec. 30. 

 A very large quantity of weed over the cage. Increase in vol- 

 ume, 78$. 



Cage 3 Planted July 6, 1 4 inches long. This cage was sunk 

 so deep that no weed was attached on the surface. The increase 

 Dec. 30 was 222$ in volume in the six months. 



Growth above the bottom 



In methods of oyster culture as developed in France, the forms 

 are placed in racks above the bottom, and from the tide which 

 sweeps over them, they are enabled to obtain nourishment enough 

 for comparatively rapid growth. It would be an interesting 

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