208 ON THE NAIADES, 



Remarks. — This remarkable species, in its great transverseness and 

 outline, has some resemblance to U. Grayanus (nobis). It is much 

 more transverse than any species heretofore discovered from this coun- 

 try. The purple of the interior is like that of the complcmatns (Soland.). 

 In one specimen there is a muscular impression near the centre of the 

 cavity of the shell, similar to that of the U. trapezoides (nobis). In 

 another specimen there are obsolete marks of an impression. The third 

 has none that can be distinguished. 



I am indebted to the great kindness of professor Shepard of New 

 Haven for this interesting and curious species, and it is with pleasure 

 I dedicate it to him. 



Unio fulvcs. Plate XIII. fig. 39. 



Testd angusto-ellipticd, inseqidlaterali, transversd, postice subangulatd ; clivo 

 umboniali rotundato ; valvulis tenuicitlis ; natihus prominulis ; epidermide luted; 

 deiite cardinali obliquo, laterali suhcurvo ,• margaritd salmonis colore tinctd. 



Shell narrow-elliptical, inequilateral, transverse, subangular behind ; umbonial slope 

 rounded ; valves rather thin ; beaks slightly elevated ; epidermis yellow; cardinal teeth 

 oblique ; lateral teeth somewhat curved ; nacre salmon. 



Hab , South Carolina. Dr Blanding. 



My Cabinet. 

 Cabinet of Dr Blanding. 

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



Shell narrow-elliptical, inequilateral, transverse, slightly inflated; 

 umbonial slope rounded; substance of the shell rather thin; beaks 

 slightly elevated, placed towards the anterior margin ; ligament thin 

 and rather short ; epidermis yellow and yellowish brown ; cardinal teeth 

 oblique, short, disposed to be lobed, single in the right and double in 

 the left valve ; lateral teeth slightly curved, rather long ; anterior cica- 

 trices distinct ; posterior cicatrices confluent; dorsal cicatrices placed in 

 the centre of the cavity of the beaks ; cavity of the beaks very shallow ; 

 cavity of the shell somewhat deep ; nacre salmon. 



