verse ribs, which are continued to the margin of the aperture, and 

 which are much widened at their bases ; with a few inequidistant 

 lightly impressed very fine spiral strias, which traverse the ribs or are 

 obsolete at their edges : spire with rectilinear outlines : apex truncate 

 with the loss of whorls: whorls remaining about six and one- 

 half, quite convex, with a deep suture : aperture ovate, widely etfuse : 

 labrum moderately reflected and thickened ; with the linguiform part 

 very obtuse and produced laterally in the lower half of the right side : 

 labium well thickened, very widely detached from the penult whorl, 

 and united to the labrum above at some distance from the extremity 

 of the latter. 



Mean divergence about 13^; length .37 inch; greatest breadth 

 .115 inch ; least breadth .1 inch. 



Geomelania CONlCA. Shell elongate conic; whitish: with, 

 on each whorl, thii-ty to thirty-five transverse slender moderately 

 arcuated ribs: spire with rectilinear outlines: apex truncate with the 

 loss of five whorls : whorls remaining seven, moderately convex, with 

 a well impressed suture : aperture ovate, rather widely effuse : labrum 

 a little expanded and reflected, with the linguiform part excessively 

 produced obliquely, and acnte, at the lower part of the right side. 



jNIean divergence about 13° ; entire length .39 inch ; greatest 

 breadth .09 inch ; least breadth .08 inch. 



Geomelania paupekata. Shell elongate conic : whitish : with, 

 on each whorl, about twenty-five rather wide obtuse transverse ribs : 



spire with rectilinear outlines: apex truncate with loss of 



whorls: whorls remaining seven to eight, quite convex, with a well 

 impressed suture : aperture ovate, slightly effuse : linguiform part of 

 the labrum but slightly produced. This species resembles G. pyg- 

 maea and G. Beardsleana. 



Mean divergence about 11° ; length .21 inch; breadth .05 inch. 



Geomelania exilis. Shell much elongated, conic-cylindrical : 

 whitish : with, on each whorl, about thirty -five transverse, very slen- 

 der, straight ribs, and numerous fine spiral striss which do not im- 

 press the summits of the ribs : spire with rectilinear outlines : apex 



truncate with the loss of whorls : whorls remaining seven, quite 



convex, with a deep suture : aperture broadly ovate, widely and 

 slightly effuse: labrum slightly expanded and reflected; with the 

 linguiform part occupying the lower half, and scarcely produced ; 

 labium as much thickened and reflected as the labrum, rather widely 

 separated throughout from the penult whorl. 



