CHIEFLY OF THE UNITED STATES. 89 



Unio Mooresianus. pi. 14, fig. 37. 



Testa lavi, subtriangulari, tumida, ad latere planulata, ad basim oompressa. postice subangulata, valde 

 inaequilaterali ; valvulis crassis, antice crassioribus ; natibus valde elevatis, tumidus ; epidermide 

 rufo-fusca, maculata, dentibus cardinalibus crassis, obtuso-conicis, crenulatis, in utroque valvulo 

 duplicibus; lateralibus crassis subrectisque ; margarita alba et iridescente. 



Shell smooth, subtriangular, swollen, flattened at the sides, compressed at the base, 

 subangular behind, very inequilateral ; valves thick, thicker before ; beaks very 

 much raised and swollen; epidermis reddish brown, spotted; cardinal teeth thick, ob- 

 tusely conical, crenulate, double in both valves ; lateral teeth thick and nearly 

 straight; nacre white and iridescent. 



Proc. Acad. Nat. Sci., 1857, p. 83. 



' Hob. — Tuscumbia, Alabama, Mr. H. Moores. 



My cabinet and cabinets of Mr. Moores, Rev. W. White and L. B. Thornton, Esq. 

 Diam. 1, Length 1-5, Breadth 1-5 inches. 



Shell smooth, subtriangular, swollen, flattened at the sides, compressed at the 

 base, subangular behind, very inequilateral ; substance of the shell thick, thicker 

 before; beaks very much raised and swollen; ligament rather thick and short; 

 epidermis reddish brown, with maculate rays; umbonial slope raised and obtusely 

 angular; posteiior slope very oblique, flattened, cordate, with an indistinct 

 impressed line from beaks to margin; cardinal teeth thick, obtusely conical, 

 crenulate and double in both valves ; lateral teeth very thick, oblique, corrugate, 

 nearly straight and disposed to be double in both valves ; anterior cicatrices 

 slightly distiiict, rather small and deeply impressed ; lateral cicatrices very distinct, 

 rather small, very well impressed ; dorsal cicatrices placed above the centre of the 

 cavity of the beaks and along the base of the cardinal tooth ; cavity of the shell 

 deep and rounded; cavity of the beaks rather deep and obtusely angular; nacre 

 silvery white and iridescent. 



Remarks. — Several specimens of this species, of various ages, are before me. It is 

 nearly allied to Edgarianus, (nobis,) but is a larger species, not so triangular, and it 

 has not the natural high polish of it. It reminds one of dollahelloides and 17iorntonii, 

 (nobis,) but it is subtriangular in its outline, and has a more flattened side and less 

 raised beaks than in the latter. The rays, in their interrupted character and their 

 becoming obsolete towards the margin, are alike. The marks of growth are very 

 much the same, being numerous. None were received in alcohol. In naming this 

 interesting species after Mr. H. Moores, of Columbus, Ohio, I have to acknowledge 

 the favor of frequently receiving species from many different habitats, and much aid 

 in various ways in investigating this family. 



