NEW FRESH WATER AND LAND SHELLS. 191 



Hab. Near Cincinnati, Ohio. T. G. Lea. 



My Cabinet, and Cabinet of T. G. Lea. » 

 Diam. .14, Length .16 of an inch. 



Remarks. — This is a very minute species recently taken in the vicinity of 

 Cincinnati,* by my brother T. G. Lea. It is very remarkable for its roof- 

 shaped spire, and two carinse, which are coloured. 



Mead October Qd, 1840. 



When I presented my last paper on the family Naiades to the society, I con- 

 sidered that but few species remained to be described, and I intended to have 

 turned my attention almost exclusively to the anatomical structure of the va- 

 rious species attainable. Circumstances have disappointed this intention, and 

 the number of new species has, owing to the kind attention of many friends, 

 increased upon my hands far beyond my expectations. Descriptions of these 

 are now made out, and many of them will be found of great interest to the stu- 

 dent of this branch of Zoology. 



Unio exiguus. Plate 7, Fig. 1. 



Testa elliftica, subcompressd; valvulis tenuibus; natibus subprominentibus ; epidermide tenebrosd, 

 virido-radiata, politd; dentibus cardinalibus lamellatis; lateralibus longis subcurvisque ; margaritd 

 caeruled et iridescente. 



Shell ova], rather compressed; valves thin; beaks somewhat prominent; epidermis dark, with green 

 rays, polished; cardinal teeth lamellar; lateral teeth long and somewhat curved; nacre blue and iridescent. 



Hab. Chatahochee River, Columbus, Georgia. Dr. Boykin. 



My Cabinet. 

 Diam. .6, Length .1, Breadth 1.7 of an inch. 



* More recently found by Dr. Troost in the Holston, Tennessee. 

 VIII. — 2 Y 



