58 



LAKD AND FRESH-AVATER SHELLS OF N. A. [PART IV. 



Fig. 111. 



on : New Harmony, Indiana ; Mr. Carlcy and Mr. Sampson : Warrior 

 River, Alabama; Prof. Brumby. 



Diameter, -07; length, 1-53 inches. 

 Observations. — This is among the largest species of 

 the Melanidiii which inhabit the waters of the United 

 States. It has usually been considered a variety of 

 Nelania {Tr>jpanostoma) undulata, Say, but it is easily 

 distinguished by its being longer and narrower in the 

 outline, in having a greater number of whorls, and iu 

 having moi'e and smaller tubercles on the periphei-y of 

 the last whorl. This usually has twelve or thirteen, 

 while ioichikita has seven or eight. Few individuals 

 are without bands, and there are usuallj^ two broad ones 

 more distinct within than without. These two bands are sometimes 

 separated into four. The first three or four whorls are usually carinate. 

 The tubercles, which are usually beautifully defined, are highlj' orna- 

 mental, but usually do not exist above the ultimate and penultimate 

 whorls. This species seems to be widely distributed, and few or none 

 of our species are more beautiful. There is usually a revolving 

 raised line above, and parallel with, the row of tubercles. The color 

 of the epidermis varies much. Some specimens are of a rich straw 

 yellow, and others are greenish, while others again are of a deep 

 olive-brown, with a fine natural polish. Some have the upper band 

 so broad that a single whitish line is visible under the 

 suture. This may be remarked more particularly in 

 the specimens from the vicinity of New Harmony. 

 The aperture is about one-third the length of the 

 shell. — Lea. 



lo nodosa. — Shell tubei'culate, raised, conical, green- 

 ish horn-color, banded ; spire irregularly conical ; sut- 

 ures very much impressed ; whorls about ten, flattened, 

 tubcrculate on the middle, striate below; aperture 

 rather small, rhomboidal, banded within; outer lip 

 sharp and sigmoid; columella white and very much 

 twisted ; canal rather short. 



Operculum \>yv\iovTa, spiral, dark chestnut-brown, with the polar 

 point near to the basal margin. 

 Habitat. — Tennessee River, Alabama? Wm. Spillman, M. D. 

 Diameter, -57; length, 1-58 inches. 



Fig. 112. 



