92 



anterior side slightly contracted or furrowed from 

 beak to base; basal margin slightly emarginate; epi- 

 dermis straw-coloured, polished; within white; car- 

 dinal teeth double in each valve; lateral teeth slightly 

 arcuate. 



SYNONYME. 



U. stramineus, Nob. New Fresh Water Shells, pi. vii. fig. 3. 

 Cab. A. N. S., No. 20420. 



OBSERVATIONS. 



Inhabits brooks or mill streams in Greene county, 

 Alabama. 



This species may be compared to some varieties 

 of siliguoideus, but is sufficiently distinct, being desti- 

 tute of rays on the disk, and having remarkably 

 prominent lines of growth. The siliquoideus has not 

 been found in Alabama. 



UNIO PATULUS. 



Plate L. — Fig. 2. 

 DESCRIPTION. 



Shell ovate; convex anteriorly, and compressed 

 and cuneiform posteriorly; substance of the shell thick 

 on the anterior and thin on the posterior side; beaks 

 not terminal, prominent, undulated, almost contigu- 

 ous; umbonial slope undefined or obtusely rounded; 

 epidermis brownish-yellow, with broad interrupted 

 green rays composed of fasciculi of hair like lines; 

 within white; cardinal teeth, in the left valve pro- 



