NEW UNIONID.E OF THE UNITED STATES. S9 



Unto concoloe. PI. 12, fig. 237. 



Testa laevi, oblique elliptic;!, subiuflata, insequilaterali, postice subbiangulata, antice rotunda; valvulis 

 subcrassis, antice crassioribus ; natibus subprominentibus; epiderniide tenebroso-oliva, eradiata, ad urn- 

 bones nitida, inferno striata ; dentibus cardinalibus crassiuseulis, erectis, obtuse compressis ; laterali- 

 bus sublongis, obliquis subrectisque j margarita alba et iridescente. 



Shell smooth, obliquely elliptical, somewhat inflated, inequilateral, subbiangular be- 

 hind, rounded before ; valves rather thick, thicker before; beaks rather prominent; 

 epidermis dark olive, without rays, bright towards the beaks, striate below ; cardinal 

 teeth somewhat thick, erect, obtusely compressed ; lateral teeth somewhat long, ob- 

 lique and nearly straight ; nacre white and iridescent. 

 Proc. Acad. Nat. Sci. 1861, p. 40. 



Hah. — Big Prairie Creek, Alabama. E. R. Showalter, M. D. 



My cabinet and cabinets of Dr. Showalter and Dr. Lewis. 

 Diam. -8, Length 1-3, Breadth 2 inches. 



Shell smooth, obliquely elliptical, somewhat inflated, inequilateral, subbiangular 

 behind, round before ; substance of the shell rather thick, thicker before ; beaks rather 

 prominent ; ligament rather large and dark brown ; epidermis very dark olive, with- 

 out rays, shining on the umbones and striate below ; umbonial slope slightly raised 

 and very obtusely angular; posterior slope rather narrow, very slightly raised, with 

 an indistinct impressed line on each valve from the beaks to the posterior margin, with 

 four or five rather close marks of growth ; cardinal teeth somewhat thick, erect, ob- 

 tusely coompressed, oblique ; lateral teeth rather long, oblique and nearly straight ; 

 anterior cicatrices distinct, rather small and well impressed; posterior cicatrices 

 confluent, rather large and slightly impressed ; dorsal cicatrices placed above the 

 centre of the cavity of the beaks ; cavity of the shell rather shallow and wide ; 

 cavity of the beaks very shallow and rounded ; nacre white and iridescent. 



Soft 2Mrts. — Branchial uterus not charged, but very small ova were found in the 

 ovarium. Branchiae rather large, nearly semicircular, inner ones somewhat the 

 larger, free nearly the whole length of the abdominal sack. Palpi rather large, 

 united half way down the posterior edges. Mantle thin, with a broad, thickened 

 border colored on the margin. Branchial opening small, with a few small papillae 

 slightly colored. Anal opening small, with very small papilla; on the inner edges. 

 Super-anal opening rather large, colored on the edges and united below. Color of the 

 mass whitish, inclining to salmon. 



Remarks. — Three specimens of this species are before me — nearly all of the same 

 size. It belongs to a group of which Brumbyanus (nobis) may be considered the type 

 in regard to outline, in that character being very nearly the same; but it is not 

 allied to it in the character of the epidermis, Brumhyanus being nearly or quite black. 



