PYRAMIDELLA. 



TESTA turrita, Isevis, polita, anfractibus plu- 

 rimis, apice acuto, apertura oblongiuscula, 

 superne acuta, basi subrotundata ; labio externo 

 paululum expanse, in columellam tortam, pie- 

 rumque plieatam, sursum reflexo. 



In introducing the present Genus to our readers, we have 

 doubted the propriety of including in it several small 

 shells which have never yet been properly placed, such as 

 Helix polita, Mont.; Bulimus terebellatus, Lam,; and 

 others, but which are nevertheless more nearly related 

 to Pyramidella, than to any other Genus already estab- 

 lished. Some of these are umbilicated; others are not; 

 which is also the case with the true PyramidellcB: the 

 principal difference which we observe consists in the 

 doubtful species having no folds on the columella, but 

 inasmuch as the true PyramidellcB vary in the number of 

 these folds, some of them having only one, we are loth 

 to separate from them those shells, which, though they 

 have no fold, agree in other characters with them. We 

 therefore combine under the generic appellation of 

 Pyramidella, those shells which accord in the following 

 characters : 



Shell turrited, smooth, very rarely slightly ribbed, 

 polished; volutions numerous, apex acute; aperture ra- 

 ther oblong, acute above, rather rounded at the base; 

 outer lip slightly expanded, turned upwards at the base 

 and united to the twisted columella; columella generally 

 plaited. We have never yet had the means of ascertain-* 

 ing whether these shells have any operculum. 



