202 DESCRIPTION OF 



Shell wide, compressed, enaarginate; valves rather thick; beaks small; epidermis greenish, radiated; 

 cardinal teeth small ; lateral teeth long and somewhat curved ; nacre white and iridescent. 



Hab. Holston River, Tennessee. Dr. Currey. 



My Cabinet, and Cabinet of Dr. Currey. 

 Diam. .8, Length 1.3, Breadth 2.7 inches. 



Shell wide, compressed, emarginate; substance of the shell thin behind and 

 thicker before; beaks small, rather compressed and placed near to the anterior 

 margin; ligament long and thin; epidermis greenish with numerous obscure 

 rays over the whole disk; umbonial slope rounded; cardinal teeth small, pointed, 

 double in the left valve and single in the right; lateral teeth long, somewhat 

 curved, separated from the cardinal teeth; anterior cicatrices distinct; posterior 

 cicatrices confluent; dorsal cicatrices nearly in the centre of the cavity of the 

 beaks; cavity of the shell very shallow; cavity of the beaks very small; nacre 

 white and iridescent. 



Remarks. — This species has somewhat the aspect of a large U. iris (nobis,) 

 and the outline of a young U. suhtentics (Say.) The beaks are placed very 

 near to the anterior margin. A single specimen came into my possession. 

 More perfect ones may be found to possess more beautiful rays. 



Unio Geddingsianus. Plate 11, Fig. 15. 



Testa elUpticd, xuhinflatd ; valvulis suhtenuibus; natibus prominulis ; epidermide fused, radiatd; den- 

 tibus cardinalibiis compressis erectisque; lateralibus longis rectisqiie; margaritd alba vel salmonis colore 

 tinctd. 



Shell elliptical, somewhat inflated ; valves rather thin; beaks somewhat prominent; epidermis brown, 

 radiated; cardinal teeth compressed and erect; lateral teeth long and straight; nacre white or salmon- 

 coloured. 



Ilab. Congaree River, South Carolina. Prof. Ravenel. 

 My Cabinet, and Cabinet of Prof. Ravenel. 

 Diam. .8, Length 1.3, Breadth 2.4 inches. 



Shell elliptical, somewhat inflated, biangulate behind ; substance of the shell 

 rather thin; beaks somewhat prominent; ligament long and thin; epidermis 

 brown with numerous dark green rays over the whole disk; cardinal teeth 

 compressed, elevated, deeply divided in the left valve; lateral teeth very long 



