UNITED STATES. 17 



with numerous small dark brown papilhc on the inner edges. Sxpcr-anal openintj 

 long, united slightly below. Color of the mass whitish. 



Remarks. — This is a small oblong, transverse species in outline, and belongs to a 

 small group of which (ttricus, denlgratiis and tortivus naturally belong. It is perhaps 

 a more solid shell than either, and more cylindrical. The four specimens before me 

 all have purple nacre. The sijecimen figured is a good one, and it can easily be 

 distinguished from the allied species mentioned above; but some of the others are 

 old and worn, and look very much like tortivus. The embryonic form is very near to 

 that of iortivtis; jierhaps a little more elongate. Being so near to it, I have not 

 thought it necessary to draw it or describe it. 



Unio Woodwardianus. pi. 23, fig. 82 and pi. 29, fig. 103. 



Testa Kxvi, triangulari, ad apices erassis, postic^ biangulata, ad latere planiuscula inflequilatorall; valvulis 

 crassis, antice crassioribus ; natibus elcvatis planulatisque; epidermide luteo-olivii, striata, radiis 

 maculatis; dentibus cardinalibus parviusculis crassisque ; lateralibus pcrcrassis, crenulatis rectisque; 

 margarita argentea et iridcsccnte. 



Shell smooth, triangular, thickened at the beaks, biangular behind, incquilatt-ral ; 

 valves thick, thicker before ; beaks raised and flattened ; epidermis yellowish olive, 

 striate, with interrupted rays; cardinal teeth rather small and thick; lateral teeth 

 very thick, crenulate and straight ; nacre silver white and very iridescent. 

 Proc. Acad. Xat. Sei., 1857, p. 170. 



Hah. — Etowah and Connasauga Rivers, Cass County, Georgia. Bishop Elliott and 

 Rev. G. White. 



My cabinet and cabinets of Bishop Elliott and Mr. White. 

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



Shell smooth, triangular, thick at the beaks, obtusely biangular behind, flattened at 

 the sides, inequilateral ; substance of the shell thick, thicker before ; beaks raised and 

 flattened ; ligament very short, very thick, reddish brown ; epidermis yellowish olive, 

 striate, with dark interrupted rays intercepted by the marks of growth which are very 

 close ; umbonial slope raised into an obtuse angle : posterior slope depressed, usually 

 without any rays, but with two slightly depressed furrows from beak to margin on 

 each valve ; cardinal teeth rather small and thick, pointed, striate and crenulate ; 

 lateral teeth oblique, very thick and massive, granulate, crenulate, straight, abrupt at 

 the end and remarkably arched ; anterior cicatrices distinct and deeply impressed ; 

 posterior cicatrices distinct and well impressed ; dorsal cicatrices small, and placed under 

 the plate close to the cardinal tooth ; cavity of the shell not deep, rather wide; cavity 

 of the beaks not deep, but obtusely angular; nacre silver white and very iridescent. 



Soft parts. — PI. 29, fig. 103. Branchial uterus is placed along the outer leaf 

 in a very unusual manner. It is nearly similar to that in the U. phaseolus,Y{M.* 



* Figured by Mr. Say in Am. Conch, pi. 22, and by me in this volume, pi. 29, fig. 101 . 



