LITIIASIA. 39 



outer margin, with tlie polar point inside the left edge about one-third 

 above the basal niargia. 



Habitat. — Coosa River, Alabama; E. R. Showalter, M. D. 



Diameter, -30; length, -52 of an inch. 



Observations. — Six specimens are before me. Neither, I think, quite 

 ftiU grown. This species differs materially from Showalterii (nobis) 

 from the same i-iver. It is not quite so large, is not Inflated, but more 

 constricted on the body-whorl, and has rather distant, low, longitu- 

 dinal folds, which iu some specimens are scarcely observable. It 

 difl'ersiu having four brown bands, the Showalterii having but three. 

 The most remarkable character of fusiformis is the long, recurved 

 channel which brings it close to the genus lo. All the specimens have 

 transverse furrows, which are more strongly developed in some of 

 them than in others. The operculum is very remarkable, having the 

 margin from near to the polar point round the upper part of the 

 outer margin completely serrate. Fortunately, two of the specimens 

 were found to have the operculum adhering to the desiccated parts 

 within, and both were found to possess this peculiar character, which 

 I have never observed in any other species of the Melanidce. The ap- 

 erture is nearly two-thirds the length of the shell. — Lea. 



It is not improbable that this may eventuall}^ prove to be the 

 young of some other species — Shoivalterii, — or even Doicniei. 



13. L. Downiei, Lea. 



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

 V, iJt. 3, p. 354, t. 39, f. 227. Obs., ix, p. 17G. 



Description. — Shell sparsely nodulous, subcylindrical, chestnut-col- 

 ored ; spire obtusely conoidal, somewhat raised ; sutures irregularly 

 impressed ; whorls seven, flattened, the last rather large, 

 rhomboidal, white or banded within; outer lip sharp, sin- 

 uous ; columella white and incurved. 



Habitat. — Cumberland River; Major T. C. Downie. 



Diameter, -44 ; length, -98 of an inch. 



Observations. — This is an unusual form of Lithasia and 

 cannot be confounded with any known species. The spire 

 is exserted like most of the ITelanidce, but the aperture 

 has all the characteristics of the true Lithasia:. Its most 

 remarkable character is the formation of the few low, elongate tuber- 

 cles which it possesses. These are formed b^- an enlargemcut on 



