16 



MELANIA, Lam. 



' M. nupera. Oblong-oval; volutions five, slightly rounded; 

 body whirl with about three revolving series of subequal, equi- 

 distant, subacute granules or tubercles not higher than wide, 

 occupying the superior half of the surface; second volution 

 with but two series, remaining volutions with slightly elevated, 

 longitudinal lines, instead of tubercles; but these are often ob- 

 solete: spire towards the tip decorticated: suture not deeply 

 impressed: aperture longer than the spire; sinus of the superior 

 angle profound: labrum concave, with a callus near the supe- 

 rior angle: columella with a slight, obtuse, hardly prominent 

 angle above the sinus, which is obvious: labrum not abbreviat- 

 ed above, nor much produced near the base. 



Length, four-fifths; breadth, less than half an inch. Inha- 

 bits the Wabash River. Var. a. Body whirl with but one 

 series of tubercles. Var. b. Body whirl with four or more 

 series of tubercles. 



This species is common in the Wabash River. The spire 

 is almost invariably so completely decorticated towards the 

 apex, that no trace of the longitudinal lines remains; in the 

 young only are these lines distinct, and even in these they are 

 frequently wanting. 



M. cancellata. Shell rather slender, attenuated: volutions 

 convex, with about twenty-six reclivate, longitudinal, elevated 

 lines, crossed by about eighteen revolving ones, the eight or 

 nine towards the base crowded. 



Length, 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 differs from all 

 our species in the numerous longitudinal and transverse ele- 

 vated lines, with the exception of the catenaria, Nob., than 

 which it is of a much more elongated and attenuated form. 



-«> M. semicarinata. Shell small, rajrher slender: spire attenuated, 



acute; the four apicial volutions carinate below: volutions 

 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 

 distinguished from our other species by its small size, combined 



