Oct. 1847.] 287 



Chenopus liratus. 



Ovate, with a thick dilated labrum ; whorls nine, convex, ribbed longitudinal- 

 ly, and with revolving lines; ribs curved, undulated on the body whorl and 

 subnodose above; body whorl gibbous ; aperture narrow ; callus of the labium 

 profound. Length |. Very rare. 



I have adopted the above generic name because, as Phillipi observes, the 

 Pterocera lambis was made the type of the genus Apoorhais. 



Ringicula Mhsissippiensis. 



Ovate acute, whorls five or six, convex, with minute revolving lines ; su- 

 ture profound, margin carinated by a submarginal impressed line ; columel- 

 la two-plaited. Length 1-10. Abundant on Dr. Smith's plantation near Vicks- 

 burg. 



Actceon Andersoni. 



Oblong subovate ; whorls six, with regular impressed revolving lines, inter- 

 stices minutely striato-punctate ; spire acutely conical, whorls convex ; lines 

 on the shoulder indistinct ; aperture about equal to half the length of the shell. 

 Length 4-10. 



An elegantly formed and very rare species, dedicated to James D. Anderson! 

 Esq., of Vicksburg, who first collected the fosssils of that locality and stud- 

 ied the species. 



1. Cancellaria Mississippiensis. 

 Subovate ; whorls five or six, turreted ; ribs prominent, ten or eleven on the 

 large volution, one or two considerably larger than the others; revolving lines 

 raised, distinct, alternated in size on the lower half of the body whorl; labrum 

 striated within ; columella concave, three-plaited. Length . 



2. Cancellaria funcrata. 



Oblong ovate with large longitudinal ribs and prominent revolving lines ; 

 spire rather elevated, turreted, whorls six, convex ; two from the apex entire ; 

 ribs on the body whorl profound, unequal ; labrum with nine prominent lines 

 within, not extending to the margin ; columella three-plaited. Length J. Very 

 rare. 



1. Triton crassidens. 



Subfusiform, a little distorted ; spire acuminated ; whorls latticed, the 

 lougitudinal ridges rather distant, prominent; body whorl with the longitu- 

 dinal ribs distant, and on the angle some of them very prominent or snbtu- 

 berculous ; labrum with one large thick prominent tubercle, and with trans- 

 verse plaits and grains : columella profoundly excavated ; canal short. Length 

 1 6-10. 



I have given the name of crassidens to this species to distinguish it from T. 

 cancellinus, the large tooth on the labrum being very thick and prominent- 

 The large plait on the upper part of the labium in much smaller than the cor- 

 responding one in cancellinus. It differs in other particulars though the two 

 species are nearly allied. 



39 



