PRESn 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 subangidar; nacre white and iridescent. 



Remarks. — A single adnlt specimen only has been received from Dr. Barratt, with two 

 quite young ones. The beaks of one of these are sufliciently 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. 



Unio ineptus. PI. XV. Fig. 12. 



Testu laevi, cHip/icd, sitbco'mpressa ; viilvulis tcnuibiis; nalibus vlx prnminmlibus, ad apices uniluhilh: 

 t'pidcrmidc Valde tcncbrosa, striata; dentibus cardinalibus parvls, coniprcssis ; latcra/ibus longis, subrcctis, a 

 cardinulibus separatis ; margaritd casruled. 



Shell smooth, elliplical, 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. fubalis, (Nobis,) of our western rivers, but is still 

 more closely allied, in general form and colour, to U.faha, 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 inepliis before me has two obscure rays on the posterior slope, none being 

 apparent over the disk. More perfect specimens may present rays. 



Unio buxeus. PI. XV. Fig. 13. 



Testd Isevi, ellipticd, subinjlatu ; valvulls subcrassis; natibus subprominentibns ; epidermide tencbroso-fttscd: 

 dentibus cardinalibus subparvis erectisque ; hderalibus longis subreclisque ; margaritn alba el iridtscentr. 

 3 



