ANCULOSA. 383 



Description. — Shell much ribbed, suborbicular, thick, Very dark 

 brown, almost black, very finely striate ; spire very short ; sutures 

 much impressed; whorls inflated, covered with seven transverse ribs; 

 aperture large, nearly round, subangular above, with dark bands in- 

 side; columella thick, flattened, dark brown; outer lip very much 

 expanded and very much crenulate. 



Operculum ovate, thin, with the polar point on the inner inferior 

 edge. 



Habitat. — Coosa River, Uniontown, Alabama; Dr. E. 11. Showalter. 



Diameter, -37 ; length, -40 of an inch. 



Observations. — Several specimens of this very remarkable Anculosa 

 were sent to me by Dr. Showalter. It difl'ers from all the species I 

 have seen in its peculiar, large ribs which girt it with great strength. 

 The apices being eroded, the number of whorls cannot be j,j ^j 

 ascertained, but there are probably only three. On the sec- 

 ond whorl only three ribs appear above the suture. It ^^ 

 reminds us at once of Paludomus loricata, Reeve, but the 

 transverse ribs are not beaded like that shell. It is also a diminutive 

 shell compared with that, and has a more depressed spire. The ribs 

 are very large, and sometimes obscurely maculate. They are accom- 

 panied on the inside with dark brown bands which terminate at the 

 edge of the lip, each in a small farrow, which produces the crenu- 

 ulations of the lip. — Lea. 



The following is Mr. Reeve's description : — 



Anculosa sulcosus. — Shell ovate, rather thin, inflated, dirty-ful- 

 vous; spire very short, flat; whorls spirally keeled ; keels very large, 

 rounded, distant, with the interstices broadly excavated; aperture 

 ovate, large, wide, open ; columella short. 



Habitat. — Alabama. 



Observations. — A very remarkable Purpura-shapcd species, com- 

 posed of largely defined, winding, keel-like ribs, broadly excavated 

 in the interstices. — lieeve. 



As the species is very uniform and Mr. Anthony's types 

 before me do not in the least differ from those of Mr. Lea, 

 I Lave not considered it necessaiy to give a figure of sulcusa. 



