FAUXULUS. 251 



cesses and spaces between being represented on the outside 

 by alternate grooves and ridges. Aperture upright, irregu- 

 larly ovate, nearly closed with the following inrunning white 

 plaits: parietal 2, the first arising as a narrow thread high 

 on the body-whorl, becoming broader and contorted as it de- 

 scends, always receding inwards, to below the center of the 

 aperture, whence it is bent sharply back, embracing the pari- 

 etal wall, till it is lost sight of in the interior of the shell ; the 

 second, also arising high 011 the body-whorl, is expanded 011 

 the left till it meets the peristome, with which it combines till 

 the lobe of the labrum is reached, whence it doubles back in 

 two foliaceous folds and descends as a simple plait, receding 

 inwards and following a line parallel with the first till it too 

 is lost sight of in the interior of the shell ; labral 3, of which 

 the upper two are small, though deeply penetrating the aper- 

 ture, and rather close together; the third, though equally 

 narrow, is very long and sinuous, and as, in its progress 

 towards the interior, it embraces the expanded outer lip, it is 

 lost to sight till the far end reappears in the gullet; colu- 

 mellar 3, of which the upper two arise, thread-like, on the 

 edge of the labium, becoming stouter as they curve inwards, 

 the upper one entering at the junction of the parietal wall 

 with the columella, and the lower about the middle of the 

 columella, after taking a wide sweep towards the center of 

 the aperture ; the lowest columellar plait is smaller, but long 

 and penetrating : lastly, there are two plaits on the base of 

 the peristome similar to the lowest columellar plait. Peri- 

 stome widely expanded, but little thickened except by the 

 plaits which arise close to the margin, paler than the rest of 

 the shell, becoming white at the edges, where its outline is 

 slightly peaked at the sources of the plaits ; the ends converge 

 and are connected by a stout glossy callus reaching high on 

 the body-whorl. The labrum is strongly lobed above the 

 middle and bayed immediately below; on the lower part of 

 this lobe the peristome is slightly thickened, almost to the 

 extent of forming an eleventh plait, between which and the 

 foliated extension of the lower parietal plait is formed a partly 

 covered channel to the interior (Burnup). 



