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Lengtli^ more tlian four-fiftlis of an incli. Inliabits Florida. 
For this shell I am indebted to Capt. Leconte, who informed 
me that he obtained it in St. John’s Kiver. It differs from all 
our species in the numerous longitudinal and transverse elevated 
lines, with the exception of the catenaria, nob., than which it is 
of a much more elongated and attenuated form. 
Melania semicarinata. — Shell small, rather slender ; spire 
attenuated, acute ) the four apicial volutions carinate below ] volu- 
tions about eight, somewhat convex; suture moderately impressed; 
surface, especially of the body whirl, slightly wrinkled ; within 
slightly tinted with reddish brown. 
Length, less than half an inch. Inhabits Kentucky. 
Occurred in great numbers in a small stream. It may be dis- 
tinguished from our other species by its small size, combined 
with the existence of a carinated line only in its young state 
having increased to four volutions, the carina is no longer formed. 
Melania undulata. — Shell large, elevated, conic, brownish, 
with a broad, equally impressed band ; inferior boundary of the 
band elevated and deeply crenate; superior boundary elevated 
and sometimes nodulous : volutions at least eight, not convex : 
suture not impressed, hardly obvious, undulated by revolving on 
the inferior crenate boundary of the impressed band : labrum, near 
the base, much protruded : sinus very obtuse. 
Length, one inch and four-tenths. Inhabits the Ohio. 
I observed this large species to be abundant in Kentucky 
Kiver, when travelling in that State two years since with Mr. 
Maclure. 
It seems to approach nearest in character to the canaliculata^ 
nob., but its rough appearance will distinguish it, even at first 
sight. 
Melania stygia. — Shell robust, ovate conic, black : spire 
rather longer than the aperture, eroded at tip; volutions five, hardly 
convex : wrinkles obsolete, excepting a few larger ones : suture not 
profoundly indented : aperture narrowed at base into a slight sinus 
and subangulated ; much widest in the middle : labrum much 
arquated in the middle. 
Length, three-fourths ; greatest breadth, less than half an inch. 
A specimen of this shell was given to me by Mr. Lesueur ; 
several were found in Cumberland River, by Dr. Troost. In form 
