NATURAL SCIENCES OF PHILADELPHIA. 169 



From which is obtained the formula of 6CuS, As S3 



Equivalents. Atomic weight. Calculated percentage. 



Copper 6 189.6 46.40 



Sulphur 9 144.0 35.24 



Arsenic 1 75.0 18.36 



Prom the above formula it seems not improbable that Eaargite and Stephan- 

 ite are isomorphus. 



Descriptions of Twenty-Seven New Species of TJNIONES from Georgia. 

 BY ISAAC LEA. 



Unio 8DBGIBB0SUS. Testa laevi, elliptica, compressa, valde inajquilaterali, 

 postice subangulata ; valvulis crassis, planulatis ; natibus vix promiuentibus ; 

 epidermide tenebroso-olivacea, striata, obsolete radiata ; deutibus cardinalibus 

 parvis, brevis crassisque ; lateralibus longis, crassis curvisque ; margarita vel 

 alba vel salmonis colore tincta. 



Hab. Oostenaula R'ver, Floyd County, and Etowah River, Georgia. Rev, 

 G. White. 



Unio Savannahensis. Testa laevi, oblonga, inflata, ad latere planulata. 

 postice obtuse angulata, inacquilaterali ; valvulis subcrassis, antice crassiori- 

 bu3 ; natibus prominulis; epidermide rufo-fusca vel tenebroso-fusca, obsolete 

 radiata; dentibus cardinalibus subgrandibus, pyramidatis, in utroque valvulo 

 duplicibus ; lateralibus prselongis, lamellatis curvisque ; margarita vel alba vel 

 pallida purpurea vel salmonis colore tincta et iridescente. 



Hab. Savannah River, also Brantley's Mill, Washington County, Georgia. 

 Rev. G. White, Sugar Creek, Mecklenburg County, N. C. C. M. Wheatley. 



Unio virens. Testa laevi, oblonga, subinflata, postice obttase angulata 

 valde insequilaterali ; valvulis subtenuibus, antice crassioribus ; natibus parvis 

 prominulis; epidermide virido-oliva, striata, vittata, eradiata ; dentibus cardi- 

 nalibus parvis, erectis, subcompressis crenulatisque ; lateralibus pra;longis. 

 lamellatis rectisque; margarita coeruleo-albd et iridescente. 



Hab. Georgia. Rev. G. White. 



Unio sublatus. Testa laevi, transversa, ad latere compressa, postice angu- 

 lata, valde inaequilaterali ; valvulis subcrassis ; natibus prominulis, ad apices 

 undulatis; epidermide tenebroso-fusca, valde radiata; dentibus cardinalibus 

 parvis, subpyramidatis, crenulatis, in utroque valvulo duplicibus; lateralibu.-^ 

 longis, lamellatis subrectisque ; margarita purpurea et iridescente. 



Hab. Uchee Bar, below Columbus, Georgia. Bishop Elliott. 



Unio obnubilus. Testa laevi, elliptica, compressa, postice biangulata, in- 

 aequilaterali ; valvulis subcrassis; natibus prominulis ; epidermide tencbrcso- 

 fuscfi,, eradiata, subnitens ; dentibus cardinalibus subgrandibus, subpyra- 

 midatis, crenulatis, in utroque valvulo duplicibus ; lateralibus longis, lamellatis 

 curvisque ; margarita purpurea et iridescente. 



Hab. Buckhead Creek, Burke County, Georgia. Bishop Elliott. 



Unio opacus. Testa laevi, elliptica, subcompressa, postice biangulata. 

 inaequilaterali ; valvulis subcrassis ; natibus prominulis ; epidermide vel tene- 

 broso-fusca vel nigricante, subnitens; dentibus cardinalibus subgrandibus. 

 elevatis, subpyramidatis crenulatisque ; lateralibus longis, lamellatis subrec- 

 tisque ; margarita purpurea et iridescente. 



Hab. Buckhead Creek, Burke County, Georgia. Bishop Elliott. 



Unio similis. Testa laevi, elliptica, subinflata, postice subbiangulata, valde 

 inaequilaterali; valvulis subcrassis ; natibus prominulis ; epidermide tenebroso- 



1857.J 



