220 ' DESCRIPTION OF 



Unio pusillus. Plate 18, Fig. 36. 



Testa ellipticd, subcompressd, postice angulatd; valvulis subtenuibus; natibus subprominentibus ; epi- 

 dermide tenebroso-fuscd, politd; dentibus cardinalibus minimis; lateralibus longis subcurvisque ; mar- 

 garitd albd et iridescente. 



Shell elliptical, rather compressed, angular behind ; valves rather thin ; beaks rather prominent ; epidermis 

 dark brown, polished; cardinal teeth very small; lateral teeth long and somewhat curved; nacre white and 

 iridescent. 



Hab. Ogechee River, Georgia, Major Le Conte. 



My Cabinet, and Cabinet of Major Le Conte. 

 Diam. .5, Length .7, Breadth 1.2 inches. 



Shell elliptical, rather compressed, angular behind; umbonial slope angular; 

 substance of the shell rather thin; beaks rather prominent; ligament small and 

 thin; epidermis dark brown, darker on the posterior slope; polished, furnished 

 with small obscure rays; cardinal teeth very small; lateral teeth long and some- 

 w^hat curved; anterior cicatrices distinct; posterior cicatrices confluent; dorsal 

 cicatrices placed on the under side of the plate between the cardinal and lateral 

 teeth; cavity of the shell small; cavity of the beaks very shallow and angular; 

 nacre white and iridescent. 



Remarks.— Some years since several specimens of this shell were kindly sent 

 to me by Major Le Conte. Fearing that they were young shells of some known 

 species, I deferred describing them. I have not since been able to place them 

 with any known species, and am now persuaded that they are distinct. This 

 species is somewhat allied to U. complanatus. 



Unio Javanus. Plate 18, Fig. 37. 



Testa ellipticd, subinflatd, valde in<Bquilaterali, postici subbiangulatd; valvulis subcrassis; natibus 

 vix prominentibus ; epidermide luteo-fuscd; dentibus cardinalibus minimis; lateralibus longis cur- 

 visque; margaritd albd et iridescente. 



Shell elliptical, rather inflated, very inequilateral, subbiangular behind ; valves rather thick ; beaks scarcely 

 prominent; epidermis yellowish-brown; cardinal teeth very small ; lateral teeth long and curved; nacre 

 white and iridescent. 



