﻿UNITED STATES. 199 



with numerous small dark brown papillae on the inner edges. Super-anal opening 

 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 tetricus, denigratus 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 specimen 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 tortivus; perhaps a little more elongate. Being so near to it, I have not 

 thought it necessary to draw it or describe it. 



Unio Woowardiantjs. PI. 23, fig. 82 and pi. 29, fig. 103. 



Testa lsevi, triangulari, ad apices crassis, postice biangulata, ad latere planiuscula insequilaterali; valvulis 

 crassis, antice crassioribus ; natibus elevatis planulatisque ; epidermide luteo-oliva, striata, radiis 

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

 margarita argentea et iridescente. 



Shell smooth, triangular, thickened at the beaks, biangular behind, inequilateral ; 

 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. Nat. Sci., 1857, p. 170. 



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

 Bev. G. White. 



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

 Diam. -8, Length 1*2, Breadth 1-8 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, granulatej 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, Hild.* 



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



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