312 Our Food Mollusks 



ously plowed or raked in order to loosen its surface. 

 Ordinarily this would not be necessary. 



Larger seed might perhaps be successfully plowed un- 

 der, but no experiment besides that at Bridgeport has 

 been made to test it. In the U. S. Fish Commission ex- 

 periments, clams were dropped into holes made with 

 stakes. On a pebbly beach where the making of the hole 

 was very difficult, four men at one time thus planted three 

 thousand clams in two hours. Subsequently on a sandy 

 'bottom the work was accomplished three or four times 

 as rapidly. It would not be difficult to construct wheels 

 with pegs on the rims that would . make rows of de- 

 pressions as rapidly as desired. Such a method of plant- 

 ing clams would ensure their lodgment and their proper 

 distribution, and the labor required ordinarily would not 

 be great. 



After attaining a length of more than two inches, the 

 soft clam is soon injured by exposure in summer. Tem- 

 perature, however, and not merely exposure, is the im- 

 portant factor. For several days the animal is able to 

 withstand temperatures near the freezing point appar- 

 ently without injury, but it lives only a short time out of 

 the water in warm weather. Experiments show that an 

 exposure of forty-eight hours during the hottest part of 

 the summer will lead to the death of the majority, even if 

 they are then planted, but few perished on being exposed 

 twenty-four hours under the same conditions. 



Clams to be planted, however, should ordinarily be 

 much smaller than this, and the power to resist heat in- 

 creases as size diminishes. When kept in aquaria sup- 

 plied with running water, large clams live only a few 

 days when the weather is warm; but those less than half 

 an inch long have been kept alive in a hot room, barely 



