2S BULLETIN OP THE BUREAU OF FISHERIES. 



intermediate season, when few glochidia can be found. These months, it is important to 

 note, are the height of the breeding season for most of the Quadrulas. 



MUCKET GROUP. 



We inckide in this group three abundant and important shells, the nmcket, the fat 

 mucket, and the southern niucket, and three species less abundant and less readily dis- 

 tinguished. 



The mucket, Lampsilis ligamentina (Lamarck) (Pis. I and XIII), is one of the 

 most generally distributed mussels in the United States. The commercial value 

 of the shells varies primarily with the rivers from which they are taken. The 

 muckets of the Mississippi River have not been highly esteemed. The butt (or 

 heavy) portion is considered too chalky, and the tips are rather thin. In many of 

 the shells the nacre is pink in color, which greatly reduces the value. There are, 

 however, some places in the river where the quality is superior. The muckets 

 of the Wabash River have been considered very fine, but they are now rather scarce. 

 The Yellow River, Ind., has produced excellent muckets. In the Ohio River better 

 muckets are found higher up the river. Mr. Boepple reported them abundant and of 

 good quality at Marietta, Ohio. They are abundant in the Green River, Ky., and are of 

 excellent quality in the Little Barren River, Ky. Mr. Boepple also stated that he had 

 found muckets which approached marine shell in luster in the Cottonwood River, Kans. 

 Muckets are comparatively scarce in the Illinois River, but some of the fishermen 

 believe they are becoming more numerous. 



The mucket can be found in almost any sort of stream, and the best shells are usually 

 found where there is a good current, but this is not a universal rule. In the Grand 

 River, Mich., where the current is good, the nmckets have an excellent luster, but too 

 large a proportion of the shell is very thin. 



The material works up well; it is soft and has a straight grain, although in old shells 

 the nacre splits, and the nearer to the hinge one is cutting the worse this trouble 

 becomes. Some muckets have excellent luster and clear color, but these qualities vary 

 with the locality. The color varies even in the same bed ; pink muckets and white 

 muckets are found side by side, and the cause of this difference in color is as yet unex- 

 plained. The values on the basis of ton price in 1914 and 1919, respectively, may be 

 stated as approximately $17 and $45. 



The mucket may, perhaps, liberate its glochidia to some extent in the fall, but 

 principally in spring and early summer. It has a relatively wide range of fish hosts, 

 principally among the game fishes. 



The little rainbow shell, Lampsilis iris (Lea) (PI. XIII), with its bright-green, 

 broken rays on a yellowish shell, is often mistaken for a young mucket. It is found in 

 the Ohio River system, and also in the streams of Illinois, Wisconsin, Michigan, and 

 eastward. 



The southern mucket or yellow-back mucket, Lampsilis ligamentina gibba Simpson 

 (PI. XIV), one of the finest of all shells, differs from the conmion mucket in being 

 shorter and more compressed. The shell is therefore flatter and the thickness more 

 even; the textureandluster are unsurpassed, and the material works easily and econom- 

 ically. This form is found in streams south of the Ohio River and perhaps, too, in that 



