250 Pearls. 



fresh-water mussels of Russia and of France. In 

 1849, I^r. Adolphe de Bauran performed numerous 

 experiments on the production of Pearls by the 

 mussels (Unio margaritifer) of the torrential stream 

 of Vianz, near Rhoder, in the department of Aveyron. 

 His experiments were not followed by any striking 

 success. Even less successful were the attempts to 

 produce Pearls in the Unio littoralis, of the Touch, 

 near Toulouse, as conducted by MM. Mouquin- 

 Tandon and Jules Cloquet, who, in 1858, read a paper 

 on this subject before the Societe d' Acclimatation of 

 Paris. 



American River Pearls. 

 In many of the rivers flowing through the 

 northern part of the American Continent, the Pearl- 

 mussel is abundant. Dr. Isaac Lea, of Philadelphia, 

 has catalogued many hundreds of species of American 

 river-mussels belonging to the genera IJnio^ Marga- 

 ritana and Anadon. Yet the occurrence of good 

 Pearls in these shells does not appear to be frequent. 

 At any rate, the business of Pearl-fishing, involving 

 as it does, great expense in a country where the 

 value of labour is high, has not hitherto been a 

 very remunerative industry. 



River-Pearls have been systematically fished in 

 the Miami river, in Warren county, Ohio. The 



