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260 NEW MELANIDiE OF THE UNITED STATES. 



diameter, it will be seen that the proportions differ very much from that species. 

 It cannot be confounded with Lithasia semigranulata (Melania, Desh.), for that 

 species is always more raised in the spire and studded with numerous rather small 

 tubercles. It is more closely allied to Melania (Liihasia) salebrosa, Con., but that 

 species has a lower spire, has larger and usually more tubercles, and these, if not 

 vertical, incline to the left, while those on Tuomeyi are irregular and incline very 

 much to the right, the number on the specimen before me being five on half of the 

 last whorl. It is closely allied to Melania (Lithasia) Florentiana, (nobis,) but differs 

 much in the tubercles, in being a heavier shell, less acuminate, in being thicker on 

 the columella and less open in the channel. The Tuomeyi is much thicker above and 

 below on the columella, has three obscure bands within, and the outer lip is thick- 

 ened and white inside the edge. 



This species and imperialis were accompanied by many specimens of semigranata 

 and Florentiana. The exact habitat was not mentioned. I have peculiar pleasure 

 in dedicating this species to my friend, the late Professor Tuomey, whose able 

 report on the geology of S. Carolina and Alabama have justly gained him so 

 much reputation. 



Lithasia dilatata. PI. 35, fig. 69. 



Testa lasvi, subglobosft, subcrassa, glauco-virente, infra suturis luteolft, obsolete vittata; spira obtuse 

 conoidea ; suturis irregulariter inipressis ; anfractibus quinis, ultimo grandi et ventricoso ; apertura 

 graudi, subrhomboidea, intus fusceseente, ad basim angulata ; columella inferne et superne 

 incrassata, incurvS,; labro acuto et valde dilatato. 



Shell smooth, subglobose, rather thick, greyish green, yellowish below the sutures, 

 obscurely banded ; spire obtusely conical ; sutures irregularly impressed ; whorls five, 

 the last one large and ventricose ; aperture large, subrhomboidal, brownish within and 

 angular at the base; columella thickened above and below, incurved; outer lip 

 sharp and much dilated. 



Lithasia dilatata, Proc. Acad. Nat. Sci., 1861, p. 55. 



Hob. — Tennessee, Dr. Troost. 



My cabinet and cabinet of the Smithsonian Institution. 

 D; am. -45, Length -73 inch. 



Remarks. — This is a well-characterized species, nearly allied to two species which 

 I described some years since before Lifliasict was established, under the names of 

 Melania Florentiana and M. venusta, 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 color interrupted by light, trans- 

 verse, fine lines. On the upper part of body whorl there are several low tubercles, 

 which may not be found in all the individuals of this species. The callus above is 



