FRESH WATER AND LAND SHELLS. 17 
and slightly elevated; anterior cicatrices distinct; posterior cicatrices confluent; dorsal 
cicatrices within the cavity of the beaks; cavity of the shell deep and rounded; cavity of 
the beaks shallow and subangular; nacre white and iridescent. 
Remarks.—A single adult specimen only has been received from Dr. Barratt, with two 
quite young ones. The beaks of one of these are sufficiently perfect to show that the 
undulations extend some distance from the point, and that they are rather complex. The 
young are rayed over the whole disk. ‘The adult specimen has many dark-green rays 
over the posterior portion, but none on the anterior portion. This species is somewhat 
like Unio cariosus, Say, but is more regularly elliptical and more transverse. ‘The young 
specimens very much resemble the young of U. radiatus. 
Unto rneptus. Pl. XV. Fig. 12. 
Testa levi, ellipticd, subcompressd; valvulis tenuibus; natibus vix prominentibus, ad apices undulatis ; 
epidermide valdé tenebrosa, striata; dentibus cardinalibus parvis, compressis ; lateralibus longis, subrectis, a 
cardinalibus separatis; margarita ceruled. 
Shell smooth, elliptical, somewhat compressed; valves thin; beaks scarcely prominent, undulated at the beaks; 
epidermis very dark and striated; cardinal teeth small, compressed; lateral teeth long, nearly straight and sepa- 
rated from the cardinal tooth; nacre bluish. 
Hab. Abbeville District, S.C. J. P. Barratt, M.D. 
My cabinet. 
Diam. .4, Length .7, Breadth 1.3 inches. 
Shell smooth, elliptical, somewhat compressed, rounded before and subangular behind; 
substance of the shell thin; beaks small, scarcely prominent; undulated rather coarsely at 
the tip; ligament short and thin; epidermis much striated, very dark-brown, nearly black; 
umbonial slope rounded; marks of growth indistinct; cardinal teeth small, compressed, 
crenulate, double in the left and single in the right valve; lateral teeth long, nearly straight, 
thickened at the posterior end; anterior cicatrices distinct; posterior cicatrices confluent; 
dorsal cicatrices placed nearly in the centre of the cavity of the beaks; cavity of the shell 
very shallow; cavity of the beaks very shallow and angular; nacre bluish. 
Remarks.—A single specimen only of this species is before me, and may not be adult. 
It is quite small, and somewhat like U. fabalis, (Nobis,) of our western rivers, but is still 
more closely allied, in general form and colour, to UJ. faba, D’Orb. It differs from the 
former in being a thin shell, and having a more elevated posterior slope, and from the 
latter in having the sides more compressed, and in the beaks having irregular undulations, 
while the faba has the radiated folds so peculiar to most of the South American species. 
The specimen of ineptus before me has two obscure rays on the posterior slope, none being 
apparent over the disk. More perfect specimens may present rays. 
Unio suxeus. Pl. XV. Fig. 13. 
Testa levi, ellipticd, subinflatd ; valvulis subcrassis ; natibus subprominentibus ; epidermide tenebroso-fusca: 
dentibus cardinalibus subparvis erectisque ; lateralibus longis subrectisque ; margarita alba et iridescente. 
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