FRESH WATER AND LAND SHELLS. 19 
Unio rraternus. Pl. XVI. Fig. 15. 
Testa levi, elliplicd, compressa, striata, valdé inequilaterali, posticé subbiangulari; valvulis subcrassis ; 
nalibus prominulis ; epidermide tenebroso-fusca; dentibus cardinalibus parvis, tuberculatis, striatis ; laterali- 
bus prelongis subcurvisque; margarita vel alba vel purpurea et iridescente. 
Shell smooth, elliptical, compressed, striate, very inequilateral, subbiangular behind; valves rather thick ; 
beaks somewhat prominent; epidermis dark-brown; cardinal teeth small, tuberculate, striate; lateral teeth very 
long and somewhat curved; nacre white or purple and iridescent. 
Hab. Columbus, Georgia, Dr. Boykin; Abbeville District, $. C., J. P. Barratt, M.D. 
My cabinet and cabinet of Dr. Barratt. 
Diam. .6, Length 1.3, Breadth 1.4 inches. 
Shell smooth, elliptical, compressed, striate, very inequilateral, subbiangular behind, 
obtusely rounded before, flattened on the sides; substance of the shell somewhat thick, 
thinner behind; beaks somewhat prominent and placed near to the anterior margin; 
ligament long and rather thick; epidermis very dark-brown, darker on the posterior slope, 
with distant marks of growth; posterior slope compressed, with fold-like wrinkles, and 
raised into a carina; umbonial slope obtusely angular; cardinal teeth small, tuberculate 
and striate; lateral teeth very long, somewhat curved, thicker at the posterior end and 
separated from the cardinal tooth; anterior cicatrices distinct; posterior cicatrices con- 
fluent; dorsal cicatrices placed in a row on the interior of the plate; palleal cicatrix 
impressed; cavity of the shell very shallow; cavity of the beaks very shallow and rounded ; 
nacre white or purple and iridescent. 
Remarks.—This species belongs to the group of which UW. complanatus is the type. It 
is closely allied to U. Hopetonensis, (Nobis,) but differs in being more elliptical in the out- 
line, and having a less elevated carina, and in the cardinal teeth, which are not compressed. 
The outline is more that of Unio Hembeli, Con., but it is not so thick a shell, and does 
not possess the coarse folds on the posterior slope, which in that species distinguish it so 
well. The Hembeli is also darker, the striae coarser, and the umbonial slope more rounded, 
Of the six specimens before me, two are white, three purple, and one slightly salmon 
coloured. The margin is broad and dark coloured. 
Unio Cuvierianus. PI. XVI. Fig. 16. 
Testa levi, elliptica, convexa, inequilaterali, posticé obtuse angulata; valvulis crassis ; nalibus prominulis; 
epidermide nitida, castaneo-fusca; dentibus cardinalibus magnis crenulatisque; lateralibus prelongis sub- 
curvisque; margarita argentea. 
Shell smooth, elliptical, convex, inequilateral, obtusely angular behind; valves thick; beaks a little prominent; 
epidermis shining, chestnut-brown; cardinal teeth large, crenulate; lateral teeth very long and somewhat curved; 
nacre silvery white. 
Hab. Washington county, Georgia, Rev. G. White. 
Cabinet of Major Le Conte. 
Diam. 1.5, Length 2.2, Breadth 3.9 inches. 
Shell smooth, elliptical, convex, inequilateral, obtusely angular behind, inflated over the 
umbones; substance of the shell very thick; beaks bnt slightly prominent and submedial; 
