PEARLS. 101 
Mya-margaritifera: Pearl-Muscle. 
At present the Pearl fisheries of South America are 
principally confined to the gulf of Panama, and the 
mouth of Rio de la Plata, to the coast which sur- 
rounds Cubaqua, to the vicinity of Araga, and Coche, 
and to the island of Margaretta. But these, as I 
have previously observed, are less productive; the 
Pearls also, which they produce, are not so brilliant 
as on the first arrival of the Spaniards. A fact 
which has exercised the ingenuity of several distin- 
guished naturalists,—for who can explore the trackless 
basin of the sea? Earthquakes may have altered its 
general character, or subterraneous currents exercised 
