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lions flooded by backwater from the locks have no current, and tongs 

 are required, but the quiet water forms a favorable breeding place 

 for mussels and the beds grow faster and thrive better than in a 

 swift current. Unlike the upper Mississippi, there is little or no 

 independent clamming on the Cumberland. In most cases the clam- 

 mers do not own their outfits, but collect the mussels by contract 

 for the person furnishing the boats. 



On account of the high percentage of pink shells, clamming is 

 not very profitable in the upper portion of the Cumberland, but if 

 the southern mucket were artificially propagated there it would 

 soon reduce this percentage and make the mussel beds commercially 

 valuable. 



THE IMPORTANT SHELLS. 



Eighty-six species of mussels are now known from the Cumberland 

 River, of which only about 17 can be used for button making, the 

 rest being too small or too thin. Among these 17 there are but 5 

 really important species — the niggerhead, the Ohio River pig-toe, the 

 southern mucket, the butterfly, and the yellov\^ sand shell. 



The niggerhead {Quadrula ehena) is the most important shell on 

 the lower river, but the means of propagating it have not yet been 

 discovered. It is doubtful whether it would succeed in any but the 

 lower part of the river, as it requires rather deep water, and it has 

 probably extended its range up the river as far and as abundantly as 

 it found conditions favorable. 



The Ohio River pig-toe {Quadrula otliqua) is the most common 

 commercial shell in the central portion of the river. While a good 

 button shell, it is considerably inferior to the niggerhead, and since 

 better shells are easily procurable, this one would not make a par- 

 ticularly desirable species to propagate in the river unless the con- 

 ditions were especially favorable. 



The southern mucket {Lampsilis ligamentinus gibhus) is an un- 

 usually good button shell, fully equal to the best of the niggerheads. 

 It is quite flat and uniform in thickness, so that there is little waste. 

 It could be easily propagated, since it has a long breeding period, 

 and the glochidia fasten themselves readily to sunfishes, perch, and 

 bass. It will thrive also in a great variety of situations, so that, 

 everything considered, it would be much superior to any other species 

 for the restocking of the river. 



The butterfly {Plagiola securis) is rather common throughout the 

 whole length of the river. Near the mouth of the river the shells 

 are badly stained, but above Canton, Ky., they have an excellent 

 white nacre. The species reaches a large size in the Cumberland, 

 and the sexes are strongly marked, the females being humped and 



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