10 NEW UNIONIDiE, MELANIDiE, ETC.. 



Hah. — Livingston's Creek, Brunswick Co., North Carolina, E. Emmons, M. D. 



My cabinet and cabinet of Dr. Emmons. 

 Diam. '5, Length '9, Breadth 1-6 inches. 



Shell smooth, elliptical, inflated, very inequilateral, subbiangular behind" and round 

 before; beaks somewhat prominent; substance of the shell rather thin; ligament 

 short, thin and dark brown ; epidermis reddish brown or brownish green, radiate, with 

 distant marks of growth, polished on the sides towards the beaks; umbonial slope 

 raised, obtusely angular or rounded ; posterior slope somewhat broad, usually with 

 capilliary rays, slightly carinate; cardinal teeth small, obtusely conical, crenulate, 

 double in both valves ; lateral teeth rather long, lamellar and somewhat curved ; 

 anterior cicatrices distinct, rather large and well impressed ; posterior cicatrices con- 

 fluent, rather large and very slightly impressed ; dorsal cicatrices small and placed 

 over the centre of the cavity of the beaks ; cavity of the shell rather deep ; cavity of 

 the beaks shallow and rounded ; nacre bluish white and very iridescent. 



Remarks. — More than a dozen of this little species were received from Dr. Emmons. 

 None of these were colored in the nacre, except that a few were tinted with salmon in 

 the cavity of the beaks. The older ones have lost the polish on their umbones, as 

 well as the rays, which are almost capillary and usually cover the posterior half of 

 the disk. The beaks of all the specimens were eroded, so that the character of the 

 undulations could not be ascertained. 



This species is nearly allied to pusillus, (nobis), but it is smaller, not so narrow an 

 ellipse, is of a thinner nacre, and smoother and more polished on the sides and towards 

 the beaks. The umbonial slope is also usually more raised. 



Unio viridulus. pi. 3, fig. 7. ■ 



Testa laevi, lata subcompressa, ad latere planulata, valde incequilaterali ; valvulis tenuibus, antice ad 

 marginem parum crassioribus ; natibus prominulis, ad apices undulatis ; epidermide virente, obsolete 

 radiata, valde polita ; dentibus cardinalibus parvissimis, tuberculatis ; lateralibus longis, aeicularis 

 subrectisque ; margarita caeruleo-alba et valde iridescente. 



Shell smooth, wide, rather compressed, flattened at the sides, very inequilateral ; 

 valves thin, somewhat thicker at the anterior margin; beaks a little prominent, un- 

 dulate at the tips ; epidermis greenish, obscurely radiate, very much polished ; cardinal 

 teeth very small, tuberculate ; lateral teeth long, acicular and nearly straight ; nacre 

 bluish white and iridescent. 



Proc. Acad. Nat. Sci. 1863, p. 193. 



Hah. — Neuse River, near Raleigh, North Carolina, E. Emmons, M. D. 



My cabinet. 

 Diam. "31, Length -52, Breadth 1-34 inches. 



Shell smooth, wide, somewhat compressed, flattened at the sides, very inequilateral, 



