CHIEFLY OF THE UNITED STATES. 259 



concentrically folded at the tips ; epidermis minutely striate, brownish or greenish, 

 radiate ; cardinal teeth small, compressed, corrugate, double in both valves ; lateral 

 teeth rather long and somewhat curved ; nacre pale purple and very iridescent. 

 Proc. Acad. Nat. Sci. 1865, p. 89. 



Rah. — Kiokee Creek, near Albany, Dougherty Co., Ga., B. M. Cromwell, M.D 



My cabinet and cabinets of Dr. Cromwell and Mr. Hallenbeck. 

 Diam. -4, Length -7, Breadth 1-1 inch. 



Shell smooth, elliptical, somewhat inflated, very inequilateral, rounded before and 

 round behind; substance of the shell thin, thicker before; beaks somewhat promi- 

 nent, concentrically folded at the tips; ligament small, thin and rather light brown; 

 epidermis minutely striate, brownish or greenish, with a few broad green rays, with 

 distant broad marks of growth ; umbonial slope rounded ; posterior slope regularly 

 elliptical, carinate, with two broad yellowish rays on each valve ; cardinal teeth 

 small, compressed, corrugate, double in both valves ; lateral teeth rather long and 

 somewhat cui'ved; anterior cicatrices scarcely distinct, rather large and well im- 

 pressed; posterior cicatrices confluent, rather large and slightly impressed ; dorsal 

 cicatrices placed over the centre of the cavity of the beaks ; cavity of the shell rather 

 deep and wide; cavity of the beaks small and obtusely angular; nacre pale purple 

 and very iridescent. 



Remarlcs. — Mr. Hallenbeck sent me a suite of fine specimens of this pretty little 

 species. At first I thought it might be a variety more perfect than usual o? paidus 

 (nobis), although closely allied to that species. The two yellow rays on the posterior 

 slope of each valve are larger and more distinct, and the carina is higher. It also 

 difiers in the undulations of the beaks, and is rather thinner. The nacre in all the 

 five specimens is purple, which is not the case with ihQ paulus. In the nacre and in 

 the outline it is allied to ()lans (nobis), but in the epidermis and beaks it is entirely 

 different, as well as being a. thinner shell. It belongs to that group of which parvus 

 (Barnes) may be considered the type, but differs in the epidermis, the nacre and the 

 undulations of the beaks. I name it after Dr. Cromwell, who found it and gave it to 

 Mr. Hallenbeck. 



Unio Lyonii. pi. 32, fig. 74. 



Testa Isevi, subrotunda, subcompressa, insequilaterali ; valvulis subcrassis, antice crassioribus ; natibus 

 promineutibus ; epidermide rufo-fusca, late radiata ; dentibus cardinalibus subgrandibus, sub- 

 compressis corrugatisque ; lateralibus crassis, obliquis subcurvisque ; margarita dilute salmonea et 

 valde iridescente. 



Shell smooth, subrotund, somewhat compressed, inequilateral; valves rather thick, 

 thicker before; beaks prominent; epidermis reddish-brown, with broad raysj 



