TO rafinesque's 



my travels of 1818 and 1819, and figured 28 of them. This labour 

 ■was written at Lexington, in January 1820, and published in French, 

 at Brussels, in September 1820, in the General Annals of Physical 

 Sciences, by Bory and Drapiez, and also in a separate pamphlet. I 

 stated then, that several other species existed in the Western Waters, 

 but described none but those I had before ray eyes. I have, how- 

 ever, diligently collected these additional species, in my successive 

 travels between 1820 and 1826, and have thus added, at least 40 

 species to the 75 already described ; some of which, must also form 

 peculiar Genera, or Sub-genera, particularly the Lasmonos, which 

 fills the gap in the variety of hinges. We have thus five different 

 tribes of Bivalve shells. 



1. Unio. Hinge, with a cardinal tooth and a lamellar tooth. 



2. Alasmodon. Hinge, with a cardinal tooth only. 



3. Lasmonos. Hinge, with a lamellar tooth only. 



4. Anodonta. Hinge, without teeth. 



5. Cyclas. Hinge, with two lamellar teeth. 



My labor on this branch of conchology, of which I was the pioneer 

 and first historian, has attracted a great deal of attention in Europe, 

 and latterly, also, with us. I was repeatedly asked for the shells I 

 had discovered and described ; I disposed of some rare ones, for the 

 Museum of my friend Clifford, in Lexington, and for the Museum of 

 Transylvania University. I furnished several to my friends, Elliot, 

 Collins, Graham, Hart, &c., in America, and Eerusac, Brnogniart, 

 Swainson, Sowerby, &c., in Europe. Meantime, I have lately found 

 that these fine shells have acquired a great value in Europe, and 

 some have sold at very high prices in England, Germany and France, 

 while I have seldom derived any profit from them, but much trouble, 

 expense, and even vexation. I am determined to dispose of none left 

 me, but for sale ; I have as yet 400 specimens, or 60 species, of ray 

 Monograph in my cabinet, and all those described in this continua- 

 tion, about 96 species in all, which I value from one to five dollars 

 each ; and even 5 species at ten dollars or more, being perhaps 

 unique specimens. I offer them for sale, and have begun to sell 

 upwards of 50 to Mr. Ch. A. Foulson, for his fine cabinet in 

 Philadelphia. 



Some of these shells are so very rare, that I have only met them 

 once in 4,000 miles of travels and explorations ; others I have never 

 seen, except in collections, such are the Unio ridibundus, and the 



