LITHASIA. 29 



Diameter, -43 ; length, -80 of an inch. 



Observations. — Dr. Troost sent me a single specimen of this species 

 which is very distinct, the columella is very much thick- 

 ened, particularly above, in which it resembles the genus 

 Mclanopsis. The aperture is rather more than half the 

 length of the shell. In this specimen a single obscure 

 band may be observed within, close to the base of the 

 columella. — Lea. 



This species is more narrowly cylindricul than 

 L. Florentiana; besides, it is lighter colored, heavier in tex- 

 ture, with the two deposits of callus on the columella more 

 prominent and the canal narrower and better developed. It 

 is a rather rare species. 



4. L. dilatata. Lea. 



Lithasia dilatata, Lea, Proc. Acad. Nat. Sci., p. 55, 1861. Jour. Acad. Kat. Sci., v, 

 pt. 3, p. 2C0, t. 35, f. 69. Obs., ix, p. 82. 



Description. — Shell smooth, subglobose, rather thick, grayish-green, 

 yellowish below the sutures, obscurely banded ; spire obtusely conical ; 

 Y\„ cs sutures irregularly impressed; whorls five, the last one 

 large and ventricose ; aperture large, subrhomboidal, 

 brownish within and angular at the base; columella thick- 

 ened above and below, incurved; outer lip sharp and 

 much dilated. 

 Habitat. — Tennessee; Dr. Troost. 

 Diameter, -45; length, -73 of an inch. 



Obseri-ations. — This is a well-characterized species, nearly allied to 

 two species which I described some years since, before Lithasia was 

 establisihed, under the names of Melania Florentiana and J/, vennsta, 

 both of which must be removed to the well recognized genus Lithasia. 

 It is nearest to the former, but is more globose, more glaucous and 

 darker inside, and has a larger callus above. The bands on this 

 species are very obscure, and are, indeed, simply the general colrr 

 interrupted by light, transverse, line lines. On the upper part of the 

 body-whorl there are several low tubercles, which may not be found 

 in all the individuals of this species. The callus a1)ove is tinted with 

 brown. The outer lip is bordered with white. Tlic length of the 

 best specimen is nearly three-quarters of an inch, and the aperture is 

 more than half the length of tlie shell. — Lea 



The type of Mr. Lea's description I have figured. It is, I 



