285 



Mr. Lea's communication furnishes new facts towards a geographi- 

 cal distribution of the Naiades. It contains descriptions of forty-six 

 new species of that family, two Melanise, one Carocolla and one 

 Cyclostoma. 



Of the Naiades, eleven species are from the Chatahoochee river. 

 The shells found in this river, seem to differ from those of the waters 

 that fall into the Atlantic, as several of the species have folds ; and 

 also from those of the Ohio and its eastern tributaries, as none of 

 them have tubercles ; — facts which are curious, inasmuch as the head 

 waters of the Chatahoochee are not far distant from those of some 

 of the Atlantic rivers, on the one side ; and, on the other, from some 

 of the tributaries of the great river Tennessee, which falls into the 

 Ohio. 



Two interesting species are from New Holland, one of which has 

 a double wing ; and three are from Java. 



The whole number of recent species of Naiades admitted by Mr. 

 Lea, is 369; being 282 more than Lamarck described. 



Unio cucumoides. Testa, plicate, latissima, emarginata, subcylindracea; 

 valvulis subcrassis; natibus vix prominentibus; epidermide nigra; dentibus 

 cardinalibus parvis, tuberculatis; lateralibus longissimis rectisque; margarita 

 alba. Hab. Hunter's River, New South Wales. — Dr. Jay. 



Unio delphinus. Testa alata, lata, compressa, postice biangulata, valde in- 

 aequilaterali; ala elevata, acuminata, duplici; valvulis subcrassis; natibus vix 

 prominentibus; epidermide tenebroso-fusca ; dentibus cardinalibus parvis, 

 crenulatis; lateralibus longissimis rectisque; margarita alba et iridescente. 

 Hab. New Holland — G. Von den Busck, M.D. 



Unio orientalis. Testa transversa, subinflata, valde insequilaterali; valvulis 

 subcrassis; natibus sub-prominentibus, ad apices undulatis; epidermide lutea, 

 nitida; dentibus cardinalibus longis; lateralibus longis subcurvisque; marga- 

 rita alba et iridescente. Hab. Java? — G. Von den Busch. M.D. 



Unio Javanus. Testa, ovata, subinflata, valde inaequilaterali, postice sub- 

 biangulata ; valvulis subcrassis ; natibus vix prominentibus; epidermide luteo- 

 fusca,; dentibus cardinalibus minimis; lateralibus longis curvisque ; margari- 

 ta alba, et iridescente. Hab. Java. — G. Von den Busch. M D. 



Unio Cincinuatiensis. Testa nodosa, quadrata, inflatA. emarginata, inrequila- 

 terali; valvulis crassis; natibus elevatis; epidermide lutea, valde radiata ; 

 dentibus cardinalibus subgrandibus; lateralibus sublongis rectisque; margari- 

 ta, alba. , Hab. Ohio River, Cincinnati. — T. G. Lea. 



Unio pilaris. Testa rotundata,, inflata; valvulis crassis; natibus elevatis; 

 epidermide striata, tenebroso-fusca; dentibus cardinalibus subgrandibus; later- 

 alibus longulis subrectisque; margarita alba,. Hab. French Broad and Hol- 

 ston Rivers, East Tenn. — Mr. S. M. Edgar. 



Unio Geddingsiunus. Testa, ovata, subinflata; valvulis subtenuibus; nati- 

 bus prominulis; epidermide fusca., radiata; dentibus cardinalibus compressis 



