usually a moderate current of water flowing across such shoals. The 

 presence of dead shells along shore will often give a clue to the proximity 

 of a shoal where collecting may be best. Also, in many places, the musk- 

 rats, raccoons, and mink gather mussels for food. These animals leave piles 

 of shells at their feeding grounds. Such accumulations are signs that a good 

 mussel bed is close at hand in the stream. Not only should one search the 

 stream for live specimens but such shell accumulations as are left by 

 muskrats are important sources for series of good specimens. Experience in 

 collecting at kitchen middens of muskrats shows that those animals do not 

 usually gather large specimens so that one should search in the stream for 

 some of the larger naiades. Also, the thin-shelled forms, such as Anodonta 

 and Anodontoides, are often broken by the teeth of the mammal. In any 

 event, the muskrats are usually good collectors and one may find species in 

 their refuse piles that are not easily found when working on the shoal in 

 the river. 



Many methods are employed in gathering mussels. Perhaps the oldest 

 and certainly one of the best is gathering them by simple hand picking. 

 Mussels are very sensitive to pollution and silting so that usually they are 

 common and readily seen in streams where the bottom is easily visible. 

 At first it will take a little practice to see a specimen because the animal 

 imbeds itself deeply in the shoal and often only the posterior siphons are 

 visible. One soon learns to look for the little double-holed slit that appears 

 on the bottom. This slit represents the siphonal openings through which 

 the animal breathes and gets its planktonic food. It at once becomes 

 obvious that ripples on the water due to wind or current as well as a lack 

 of sunshine — factors that hinder visibility — at times makes it almost impos- 

 sible actually to see specimens studded in the bottom of a stream. On this 

 account it is often advisable to carry a small rake with which to rake over 

 the gravel and sand of the bottom. In such an operation it is usually best 

 to move in an upstream direction as one collects on shoals. The current 

 will then carry away any suspended matter caused by raking and the shells 

 which have been uncovered can then be readily seen. Raking uncovers 

 many small specimens which might otherwise be overlooked. The use of 

 a small hand sieve is alro recommended because by sifting samples taken 

 from the bottom at various places on the shoal very young specimens 

 showing details of beak sculpture are more readily available. Such minute 

 foms are best preserved in vials containing 70 percent alcohol. To over- 

 come poor visibility in recovering small shells from the bottom, a glass- 

 bottomed bucket is often indispensable. There are some refinements of this 

 aid in overcoming the bad effects of ripples, reflections, etc. but the glass- 

 bottomed bucket is simple to make and quite efficient. 



Where shoals occur in deep water it is often necessary to use a small 

 hand dredge or a set of tongs. Such equipment, although very desirable, is 

 often cumbersome to carry and may be omitted from the list of equipment 

 actually necessary to one with only a general interest. There are, of course, 

 regions where dredges or tongs are entirely indispensable. A few years ago 

 while surveying the Ogeechee River in Georgia it was found that the lower 



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