NEW UNIONID^E OF THE UNITED STATES. 95 



Unio Ocmulgeensis. PI. 14, fig. 243. 



Testa laevi, transversa, inflata, postice obtuse biangulata, antice subtruncata, valde insquilaterali ; valvulis 

 crassis, antice crassioribus ; natibus proruinulis; epidenuide tenebroso-fusca, eradiata, superne micanti, 

 inferne valde striata; dentibus cardinalibus parviusculis, pjramidatis striatisque; lateralibus prselongis, 

 laniellatis subrectisque ; margarita aurantia et valde irideseente. 



Shell smooth, transverse, inflated, obtusely biangular behind, somewhat truncate 

 before, very inequilateral ; valves thick, thicker before ; beaks a little prominent ; 

 epidermis dark brown, eradiate, shining above and much striated below; cardinal 

 teeth rather small, pyramidal and striate ; lateral teeth very long, lamellar and 

 nearly straight ; nacre golden and very iridescent. 

 Proo. Acad. Nat. Sci. 1861, p. 38. 



Hal. — Little Ocmulgee River, Lumber City, Georgia. S. W. Wilson, M. D. 



My cabinet and cabinet of Dr. Wilson. 

 Diam. 1*3, Length 2, Breadth 4-1 inches. 



Shell smooth, transverse, inflated, obtusely biangular behind, subtruncate before 

 and very inequilateral; substance of the shell thick, thicker before; beaks a little 

 prominent, nearly terminal ; ligament long, rather thick and dark brown ; epidermis 

 dark brown, without rays, shining above, with loose, scaly stria? near the margin, 

 and with irregular, indistinct marks of growth ; umbonial slope slightly raised and 

 very obtusely angular ; posterior slope long, elliptical and slightly furrowed ; cardinal 

 teeth rather small, pyramidal, striate and crenulate; lateral teeth very long, lamellar 

 and nearly straight ; anterior cicatrices distinct, very large, corrugate and deeply im- 

 pressed ; posterior cicatrices confluent, very large and well impressed ; dorsal cicatrices 

 placed a little above the centre of the cavity of the beaks ; cavity of the shell not deep, 

 but wide ; cavity of the beaks very shallow and rounded ; nacre golden, inclining to 

 salmon, very rich and iridescent. 



Remarks. — A single specimen, and without the soft parts, was received from Dr. 

 Wilson. The beaks are much eroded, and do not, of course, give the character of the 

 undulations. It is a well marked species, with a nacre, which yields to no other 

 species in richness, being very satin-like, pure and perfectly iridescent. Younger and 

 more perfect specimens may exhibit obscure rays; this one has none whatever. In 

 outline, it is nearest to verutus (nobis), but it is a larger species, with a much darker 

 epidermis, is more inflated, the verutus being flattened on the sides. 



Uxio rubidus. PI. 14, fig. 244. 



Testa sulcata subtriangulari, valde inflata, ad latere planulata, subrcquilaterali ; valvulis subcrassis, autict- 

 crassioribus ; natibus subproiuinentibus. subinflatis; epidermide tenebroso-rufo-fusc&, eradiata. superne 

 micanti iuferne striata; dentibus cardinalibus crassiusculis, clcvatis, subpyramidatis erenulatisi|ue ; 

 lateralibus sublongis, curvis subcrassisque; margarita vel rosacea vol alba vol salmonis colore tincta 

 et irideseente. 



