NEW GENUS OP THE FAMILY MELANIANA. 123 



and to the Academy of Natural Sciences of Philadelphia, in the Jour- 

 nal of which that naturalist has described it under the name of Fitsus 

 fluvialis. Satisfied that no genus should contain pelagian and fluvia- 

 tile shells in common, I have separated this from the family Canali- 

 FERA, and placed it in that of the Melaniana to which it naturally 

 belongs. We are indebted to the research of Professor Vanuxem for 

 this and many other fine shells from the north fork of the Holston in 

 Virginia on the farm of General Preston, where it was associated with 

 several species of this and other families. Professor Vanuxem de- 

 scribes the spot which it inhabits as being very circumscribed and be- 

 ing immediately at the confluence of a small stream and the North 

 Fork of the Holston, the former of which is slightly impregnated 

 with salt. 



