IG LAND AND FRESII-WATER SHELLS OF N. A. [pART IV. 



tubercles. The last -vvhorl is so large that it nearly covers all the 

 others, leaving merely a point to mark the vertex. The two bands 

 are well pronounced interiorly as well as exteriorly. — Lea, 



Over fifty specimens of this species are before me. They are 

 closely allied to salebrosa, but uniformly much smaller, and 

 generally wider. Besides, the spire is shorter, and but very 

 few of them exhibit a slight tendency towards tuberculation 

 below the upper row. The whorls are not shouldered except 

 in .very old individuals. A very constant character of the 

 species consists in the two broad, revolving bauds of brown ; 

 a few specimens, however, have instead four narrow bands 

 approximating in pairs, and two or three are of uniform color, 

 without bands. The young differ much from the adult shells 

 in appearance. 



4. A. Tuomeyi, Lea. 



Lithasia Tuomeyi, Lea, Proc. Acad. Nat. Si., p. 55 Feb., 1801. Jour. Acad. Nat. 



Sci., V, i)t. .3, t. 35, f. G8. Obs., ix, p. 8'. 

 Anculotus Florentianus, Lea, Reeve, Mouog. Aac 1. 1, f. 4. 



Description. — Shell tuberculate, much inflated, rather thick, dark 



horn-color , spire obtusely conoidal ; sutures impressed ; whorls five, 



^. the last larce, below the sutures obliquely tuberculate ; 



Fig. 49. * ^ ■' ' 



aperture large, rhomboidal, whitish within, obscurely 



banded, channelled at the base ; columella very much 

 incurved, thickened above and below; outer lip ex- 

 panded, acute at the margin. 



Habitat. — North Alabama; Prof. Tuomey. 

 Diameter, -Gi; length, 1-0-t inches. 

 Observations. — A single specimen only was sent to me 

 by Prof. Tuomey. It was with i. imperialis, herein described. Being 

 1-04 inches in length and -64 in diameter, it will be seen that the 

 proportions differ very much from that species. It cannot be con- 

 founded with Lithasia semigranulosa, for that species is always more 

 raised in the spire and studded with numerous rather small tubercles. 

 It is moi'e closely allied to Lithasia salebrosa, Conr.,* but that species 

 has a lower spire, has larger and usually more tubercles, and these, 



* Mr. Lea conslriors L.salehrnsa and L. nenicnlata ilentical. It is witli tliG latter spe- 

 cies tbat, the comparisou is iuteuUud lu be iiiaiie. 



