28 BULLETIN OF 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 include in this group three abundant and important shells, the mucket, the fat 
mucket, and the southern mucket, and three species less abundant and less readily dis- 
tinguished. 
The mucket, Lampsilis ligamentina (Lamarck) (Pls. 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 muckets 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) (Pl. 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 
(Pl. XIV), one of the finest of all shells, differs from the common mucket in being 
shorter and more compressed. The shell is therefore flatter and the thickness more 
even; the texture and luster 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 
