28 NEW UNIONID.E OF THE 



rather long, lamellar and slightly curved ; anterior cicatrices distinct and well im- 

 pressed ; posterior cicatrices confluent and slightly impressed ; dorsal cicatrices 

 situated under the plate, posterior to the cardinal tooth ; cavity of the shell shallow . 

 and wide; cavity of the beaks shallow and obtusely angular; nacre white and very 

 iridescent. 



Remarlcs. — A single specimen of this species was sent to me many years since by 

 Dr. Boykin, and subsequently Dr. Edgar sent me a smaller one from Tennessee. 

 I have always found it difficult, on examining them, where to place them. They 

 differed in some characters from all the members of this group. I therefore deter- 

 mined, on a thorough examination of the group, to give it a distinct place. It has 

 some resemblance to Cinnb&rlandiamts (nobis), but more closely resembles fucatus, 

 herein described. It differs, however, from the latter in being smaller, more com- 

 pressed, less transverse, and in having fewer and less distinct rays ; also in being flatter 

 at the sides, which makes the basal margin almost straight. It is very near to lener 

 (nobis) in ouiline, but is a thinner shell, and not quite so flat on the sides. 



Unio fudicus. pi. 56, fig. 171. 



Testa Iscvi, subtrigomi, coiupressa, inajquilaterali, postice obtuse angulata, antiee rotunda; valvulis subcrassis, 

 antiec crassioribus ; natibus prominulis, ad apices rugoso-undulatis ; epidermidc luteo-fusca, micante, 

 virido-radiata; dentibus cardinalibus crassiusculis, erectis, compressis crenulatisquc; lateralibus subcur- 

 tis, crassis subcurvisque ; margaritfi alba et iridescente. 



Shell smooth, subtriangular, compressed, inequilateral, obtusely angular behind and 

 rounded before; valves rather thick, thicker before ; beaks riither prominent, rugosely 

 undulate at the tips ; epidermis yellowish brown, shining, with green rays ; cardinal 

 teeth rather thick, erect, compressed and crenulate ; lateral teeth rather sliort, thick 

 and somewhat curved ; nacre white and iridescent. 

 Proc. Acad. Nat. Sci., 1860, p. 92. . 



Hah. — North Alabama. Prof Tuomey, and Florence, Alabama, L. B. Thornton, 

 Esq. 



My cabinet and cabinet of Mr. Thornton. 

 Diam. -6, Length 1, Breadth 1-.3 inch 



Shell smooth, subtriangular, disposed to be subcircular, compressed, inequilateral, ob- 

 tusely angular behind and rounded before ; substance of the shell rather thick, thicker 

 before ; beaks rather prominent and rugosely undulate at the tip)s; ligament very short 

 and rather thin ; epidermis yellowish brown, shining, with small green rays more 

 fasciculate over the middle of the disk, with distant lines of growth; umbonial slope 

 slightly raised into an obtuse angle; posterior slope carinate and with few or no rays; 

 cardinal teeth erect, rather thick, compressed, crenulate and disposed to be 

 double in both valves ; lateral teeth rather short, thick, thickened at the end and 

 somewhat curved ; anterior cicatrices distinct and well impressed ; posterior cicatrices 



