12 



MUSSELS OF CENTRAL AND NORTHERN MINNESOTA. 



State and carries its mussel fauna across the line into Canada. It 

 therefore becomes of great interest to the conchologist, as well as the 

 mussel fisherman, since in it the mussels of the Mississippi Valley 

 reach the point farthest north in their migrations. In consequence 

 of the long continued glacial connection with the Mississippi, we are 

 not surprised to find the rich mussel fauna indicated in the following 

 table : 



Distribution of Mussels in Red River Group. 



Species. 



Little 

 Pine 

 Lake 

 outlet. 



Red 

 River 

 at Per- 

 ham. 



Otter- 

 tail 

 Lake 

 outlet. 



Anodonta pepiniana (paper-shell, floater) 



Anodontoides ferussacianus subcylindraceus. . 



Strophitus edentulus (squaw-foot) 



Symphynotacostata (fluted-shell) 



Sympbynotacomplanata katharinse 



Lampsilis luteola (fat mucket) 



LampsUis ventricosa (pocketbook) 



Lampsilis recta (black sand-shell) 



Quadrula coccinea (round pig toe) 



Quadrula rubiginosa (Wabash pig toe) 



The only place in this entire drainage that has ever been worked is 

 just north of Fergus Falls, where some of the country boys gathered 

 and shipped a carload of sheUs to the button factories in Iowa in 

 1910. AU of the lakes and the river are shallow and the shells must 

 be gathered with rakes or forks, or picked up by hand; there is no 

 chance for crowfoot dredges. 



QUALITY OF SHELLS. 



The mucket, the pocketbook, and the fluted shell are the principal 

 commercial mussels in the Red River. The black sand-shell is abun- 

 dant and the best shell of them all in quaHty, but as it always has a 

 dark purple nacre it can be used only for novelties. In many of these 

 northern sand-sheUs, the hinge line, instead of being straight {recta), 

 is strongly curved. But as it conforms in other particulars to a 

 normal recta, it seoms best to regard this merely as a local variation. 

 The pocketbooks also are pecuHar in being much flattened, somewhat 

 elongated, and with short and stumpy teeth, very much hke the 

 variety designated by Lea as TJnio canadensis. Many of the muckets 

 have shells as thick and heavy as those of the St. Croix drainage, but 

 there are others whose shells are thin and sometimes dwarfed like 

 lake specimens. 



The shells of nearly all the mussels which have a white nacre are 

 badly stained. These stains vary from a light-gray or drab to a dark 

 rusty brown in color. Sometimes there is but a small discoloration 



