30 



LA.ND AKD FRESH-WATER SHELLS OF N. A. [PART IV. 



think, a good species, altliough very close to L. fuliginosa. It 

 appears to be a more solid shell than that species, however, 

 and the aperture is narrower below, with a more distinct fuse. 



riff. 09. 



5. L. imperialis, Lea. 



LiOiasia impcrialis, Lea, Proc. Acad. Nut. Sci., p. 55, 1831. Jour. Acad. Nat. Sci., • 

 V, pt. 3, p. 258, t. 35, f. 67. Obs., ix, p. SO. 



Description. — Shell tuberculate, fusiform, rather thick, dark horu- 

 color; spire raised, conoidal^ sutures irregularly and much impressed; 

 whorls six, the last rather large, irregularly tuberculate above, 

 rather inflated; aperture rather small, eloagately 

 rhomboidal, whitish within, furnished with brown 

 hair-like lines, channelled at the base and recurved; 

 columella sigmoid, slightly thickened above ; outer 

 lip somewhat expanded, acute at the margin. 



Operculum rather small, very dark brown, rhom- 

 boidal, with the polar point on the left edge near the 

 base. 



Habitat. — North Alabama; Prof. Tuomey. 

 Diameter, -70 of an inch; length, 1*55 inches. 

 Observations. — This is much the largest Lithasia 

 I have seen. Although several of the whorls of the 

 vertex are eroded off, still it measures one and a half inches in length. 

 A single specimen only was received, and this without the operculum. 

 The tubercles are large aud irregular, and not much raised. The 

 capillary brown lines in the interior are numerous and rather obscure, 

 but this may not be the case with more perfect specimens. They 

 seem to replace the usual bands. They do not reach the edge, which 

 is bordered with white. Below the sutures there is a stricture which 

 nearly amounts to a furrow. It more nearly resembles Melania {Litha- 

 sia) Duttonia (nobis), than any other known species, but is a larger, 

 more ponderous species, and has not the numerous small tubercles, 

 nor tlie bands of that species. — Lea. 



B. Shell small, compact, oval-ell iptical. 

 6. L. vittata, Lea. 



Lithasia vittata, Lea, Proc. Acad. Nat. Sci., p. 273, 1862. Jour. Acad. Nat. Sci., 

 V, pt. 3, p. 351, t. 35, f. 67. Obs., ix, p. 176. 



Description.— Shell smooth, cylindrical, rather thiu, dark horn-color, 



