THE ORIGIN OF THE PEARL 23 



plished some very wonderful feats in the various tasks 

 that concern the fresh-water mussels of our country. 



Among the scientists in the Government service who 

 have contributed much valuable information are: Dr. 

 Barton, W. Everman, Chief of the Division of Scientific 

 Inquiry of the Bureau of Fisheries; George Lefevre, 

 Winterton C. Curtis, H. Walton Clark, Charles B. Wil- 

 son, S. E. Meek, Ernest Danglade and R. E. Coker, Ph. 

 D. All of these men have proved by the results of their 

 efforts that they are well qualified for this kind of work 

 for their country. It is to be hoped that all of them may 

 continue in the service in which they have proved them- 

 selves so valuable. 



While their work has been largely in the investigations 

 of the Unionidae, with reference to the various economic 

 questions relating to these mollusks, yet they have also 

 studied the origin of the fresh-water pearl. One of the 

 most important of these investigations will be mentioned, 

 viz : The report entitled, "The Mussel Fauna of the 

 Maumee River," by H. Walton Clark and Charles B. 

 Wilson. In this record eleven pages are devoted to the 

 parasites of mussels. These men found nine parasites 

 which will be described briefly : 



i. Cotylasptis insignis, Leidy. A small organism 

 which to the naked eye resembles a pale leech. The body 

 is trumpet shaped and the ventral surface has a large 

 ovate disk cut up by partitions. By this disk the animal 

 adheres to the mussel and lives in the axils of the inner 

 gills. 



It was most common in Anadonta grandis and was also 



