SCALLOP INDUSTRY OF NORTH CAROLINA 177 



HABITAT 



The bay scallop in North Carolina frequents chiefly grassy flats 

 and shallow sloughs in sounds, harbors, and estuaries where the 

 water is relatively salt. Occasionally it is found in open, muddy 

 places, and even in the ocean. It grows faster and to a larger size 

 near the outlets and other places where there is a good flow of water. 

 The consistent variation in size for near-by areas affords evidence 

 that, after an early stage of growth, extensive shifting of scallops, 

 if it occurs at all. is unusual. Even large scallops swim, but only 

 for diort distances. 



SWIMMING 



The ability of the scallop to swim is one of its most interesting 

 characteristics and probably is responsible for its economic impor- 



PiG. 2. — Scallop shell. Interior view of left and right valves 



lance. Observation reveals the fact that in swimming a scallop does 

 not move with the hinge foremost, as would be expected from the 

 action of clapping the shell, but with the free or ventral margin 

 forward, as if the animal Avas biting its way through the water. 

 This method of progression results from the action of the scallop 

 in closing the mantle around most of the free margin of the shell 

 just before it is closed, so that two jets of water are directed hinge- 

 ward and the animal is forced in the opposite direction. To give 

 these jets sufficient force, the adductor muscle (the ''edible " portion 

 of the scallop) has been developed to a great size. Hence, if it 

 were not for its habit of swimming, the scallop doubtless would be 

 used as little for food in this country as are various neglected 

 shellfish. 



The habit is to swim to the surface and then along it for a little 

 way. Occasionally a scallop, when disturbed, will close its shell 



