FRESHWATER AND LAND SHELLS. 91 



Paludina virens. Plate XXIII. fig. 93. 



Testd obliqud, crassd, subgranosd, viridi; anfractibus subinflatis ; aperturd ovatd. 



Shell oblique, thick, somewhat granose, green ; whorls rather inflated ; aperture 

 ovate. 



Hab. Wahlamat, near its junction with the Columbia river. Pro- 

 fessor Nuttall. 



My Cabinet. 



Cabinet of Professor Nuttall. 



Diam. -2, Length -4 of an inch. 



Remarks. — -The apices of all the specimens which Professor Nuttall 

 gave me are destroyed, so that it is impossible to give some of the cha- 

 racters of this species. It is remarkably solid for so small a species. 



Paludina nuclea. Plate XXIII. fig. 103. 



Tesld obtush turritd, corned, lo&vi ; suturis impressis ; anfractibus quinis ; aperturd alba, 

 ovatd. 



Shell obtusely turrited, solid, horn-colour, smooth ; sutures impressed ; whorls five ; 

 aperture white, ovate. 



Hab. Wahlamat, near its junction with the Columbia river. Pro- 

 fessor Nuttall. 



My Cabinet. 



Cabinet of Professor Nuttall. 



Diam. '2, Length -4 of an inch. 



Remarks. — This is a small solid species, and is more oblique than 

 P. decisa (Say). Like it, the apex is usually cut off. Round the 

 mouth there is a black border, which contrasts with the pale horn- 

 coloured epidermis. 



