portion of that river was so deep and the water so colored that one had to 

 rely entirely on a dredge operated from a boat to obtain an adequate 

 series of mussels. 



Another comparatively recent addition to the equipment of collectors 

 is the diving helmet. There are a variety of these, but fundamentally they 

 work on the same principle. Such helmets simply permit one to work at 

 10 or 15 foot depths to great advantage. This apparatus was recently used 

 in the Grand River of Michigan where clammers managed to clean out 

 thoroughly pockets of shells not accessible to the craw-foot bars and similar 

 equipment in use on that river. Essentially the diving helmet is merely an 

 aid for the hand-picking method of collecting. 



When specimens are gathered it is necessary to have a container in 

 which to place them. Various receptacles are used ranging from a basket to 

 bags or sacks. In our work we have found that home-made sacks of about 

 a half bushel or bushel capacity were very convenient. It is always well to 

 have a large sack because often one gets into a productive territory when 

 small ones prevent the taking of adequate series. 



After a sufficient number of specimens have been gathered it is advis- 

 able to go to a comfortable place along the shore where notes should be 

 taken about the collection. The most essential features in the note-taking 

 would include concise information giving: date and numbers of collection, 

 name of body of water, distance and direction from nearest town, the 

 county, and the state. It is well to add such ecological data as would aid in 

 recognizing a similar environment at some future date. The amount and 

 nature of the notes taken is entirely dependent upon the interest and 

 aspirations of the collector. However, it is most important that at the time 

 the locality data are written into the notebook one or more locality labels 

 be inserted into the sack or sacks containing the mus-els. Without adequate 

 locality data specimens are virtually worthless. Consequently, one cannot 

 over-emphasize the importance of accurate labels. Data should be written 

 in pencil on a good grade of label paper. Remember that mussels are often 

 dirty and wet so that an inferior label will soon become soaked and dis- 

 integrate leaving the collector with a serious problem of interpretation at 

 some later time. If one does not plan to clean the specimens until a day or 

 two later it is often well to place a small, numbered metal tag in the sack 

 at the same time tabulating that number in the field notebook. Unless the 

 shells are cleaned at once the top of the sack should be securely tied with 

 string so as to prevent any mixing of lots while one is traveling from one 

 station to another. 



When collecting it is well to take large series if they are available. 

 This is valuable not only because it gives a better appreciation of the range 

 of variation of characters within species, but also because a locality which 

 one year produces an abundance of shells may be quite depleted at some 

 later time. Often one finds it difficult to be certain in the field whether a 

 specimen is one common at the station or one not hitherto found. For 

 that reason it is safer to take good series so as to be able to distinguish more 

 carefully when the time for cleaning the specimen arrives. 



(63) 



