240 Our Food Mollusks 



oysters after a growth of but two months on a favorable 

 bottom. They have not greatly increased in size, the 

 larger ones being about two and a half inches in length ; 

 but the significant fact shown in their outlines, is that 

 immediately after being freed from their crowded con- 

 dition, they began to widen and assume the normal form. 



It may appear from some of the statements made 

 that the marginal waters of the sounds would be of 

 little value if oyster culture were to be practised in 

 North Carolina, but though clustered oysters exposed at 

 low tide are not marketable, they would become in- 

 valuable in case artificial beds were constructed in the 

 sounds, because of the vast numbers of oyster embryos 

 that they produce. These embryos, suspending them- 

 selves in the water for many hours, may be carried to 

 some distance by currents before they finally settle to 

 the bottom and make the attempt to attach themselves. 

 How far, in extreme cases, they may thus be transported 

 before becoming attached, no one is able to say. Cases 

 are known in which they have been carried several miles. 

 But spat collectors spread on bottoms near the reefs, 

 judicially selected with reference to tide currents that 

 might bear the embryos from them, would, in most sea- 

 sons, be able to gather a supply of young that, under 

 normal conditions, settle on the soft mud and perish. 



But in still another way these natural reefs are already 

 valuable, for it is from them that the existing tonging 

 grounds have arisen. Two agencies, one natural, the 

 other artificial, have been at work on the natural reefs 

 to form beds of another sort, on which a considerable 

 number of marketable oysters are found. 



If one were carefully to observe the reef oysters 

 through the various seasons of the year, he would dis- 



