142 



Lengtli, more than four-fifths of an inch. Inhabits Florida. 



For this shell I am indebted to Capt. Leconte, who informed 

 me that he obtained it in St. John's River. It diifers 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 tjndulata. — 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 : volutibns 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 

 River, 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 subaiigulated ; 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. Lcsueur ; 

 several were found in Cumberland River, by Dr. Troost. In form 



