24 rafinesque's 



fossil shells. They consist in 4 naked mollusca, of the genus Limax, 

 36 fluviatile univalve shells, 34 terrestrial univalve shells, 42 fluvia- 

 tile bivalve shells, and 10 fossil bivalve shells. Such as — (*theseare 

 fossils) — Helix, 4 species ; Planorbis, 2 ; Ancylus, 1 ; Mesomphix, 

 N. G. t. univ. 125 Trophodor, N. G. do. 10; Triodopsis, N. G. do. 

 2 ; Stenotoma, N. G. do. 1 ; Toxostoma, N. G. do. 1 ; Xolotrema, 

 N. G. do. 1 ; Aplodon, N. G. do. 1 ; Lymnula, 13 ; Pleurotoma, N. 

 G. fl. un. 12 ; Ellipstoma, N. G. do. 4 ; Bulimus, 1 ; Eurystoma, N. 

 G. fl. un. 1 ; Notrema, N. G. do. 1 ; Ambloxis, N. G. do. 4 ; 

 *Voluta, 2 ; *Solarium, 2 ; *Belemnites, 3 ; *Trochus, 3 ; *Ortho- 

 cera, 5 ; *Toxerites, N. G. un. 1 ; *Endotoma, N. G. do. 1 ; 

 *Platinites, N. G. do. 1 ; *Trigorima, N. G. do. 1 ; ""Euomphales, 

 1 ; *Patella, 2 ; *Melanites, 2 ; Mytilus, 1 ; Lepas, 1 ; Potamila, 

 N. G. fl. biv. 34 ; Truncilla, N. G. do. 3 ; Stenodon, N. G. do. 3 ; 

 Pleuroxis, N. G. do. 2 ; *Saconites, N. G. I ; *Gryphea, 5 ; *Ostrea, 

 2; *Terebratula, 24; *Productus, 15; *Spirifer, 2; *Tellina, 1; 

 *Goniclis, N. G. biv. 2 ; *Cyphoxis, IST. G. do. 5 ; *Megonma, K 

 G. do. 4 ; *Oxisma, N. G. do. 1 ; *Curvula, N. G. do. 3 ; *Apleu. 

 rotis, N. G. do. 2; *Pachosteon, N. G. do. 1. 



[356] 

 Description of a new Genus of Fluviatile Bivalve Shell, of the 

 family of Brachiopodes ; Notrema Fissurella ; in a Letter to 

 Dr. S. L. Mitchill, Prof of Nat. Hist. &c., New York. 

 Dear Sir : 



There is a small family of bivalve shells, which have received the 

 name of Brachiopodes, distinguished by having tentacula. It con- 

 tained, in my Analysis of Nature and in Cuvier's Regne Animal, 

 only three genera, lingula, orhioula and terebratula, all maritime; 

 this last, whicn is very numerous, particularly in fossil species, has 

 lately been divided by Sowerby, who has established the genera Pro- 

 ductus and Spirifer ; and I have added another fossil genus. 

 Apleurotis, distinguished from it by being elongated, obliquatcd, 

 and auriculated on one side only, in a memoir presented to the 

 Academy of National Sciences of Philadelphia. 



In my travels on the Ohio, I have ascertained another genus 

 belonging to that family, which is very similar to the genus Orbi- 

 cula ; but it is fluviatile, and the larger or upper valve is perforated 

 in the middle as in Fissurella, and operculated. I have not seen 

 the living animal myself; but Mr. Audubon of Hendersonville, a 

 zealous observer, has drawn it, and it appears to have a head with 



