318 PYRAMIDELLID^. 



The curious truncation of the apical whorls which occurs 

 in adult examples of this very local shell, induced Mon- 

 tagu to regard it as a different species from its turreted 

 young. 



When adult, the shell is almost cylindrical, more or 

 less narrow, rather thin, a little translucent, and of an 

 uniform shining, pale-reddish, tawny hue. Beneath the 

 suture the surface is longitudinally crenated with very 

 numerous and short narrow folds, and the bases of the turns 

 are oftentimes corrugated, likewise, by a similar but less 

 manifest sculpture ; elsewhere the shell is smooth, or very 

 nearly so, and occasionally in the adult, and nearly always 

 in the young, the markings are almost entirely absent. 

 In the immediate vicinity of the outer lip the wrinkles 

 extend right across the body. This last, whose base is 

 well rounded, and whose declination is early, gradual, 

 and decidedly convex, is about a third shorter than the 

 united three whorls, that alone, in that state of growth, 

 remain of the spire. These turns are rather high, almost 

 equally as broad above as below, and although swelling out 

 more or less (and often abruptly) from each suture, cannot 

 well be termed ventricose, being somewhat flattened in 

 the middle : the suture which divides them from each 

 other is rather oblique, and though simple, very profound. 

 The mouth, which is not adorned with any sculpture, is 

 very short, merely occupying about two-sevenths of the 

 total length ; it has a greater or lesser lateral projection, 

 and a subovate contour, and is not angularly contracted 

 above, though less broad than at its rounded base. The 

 peristome is complete, and the enamel is very broadly 

 spread upon the upper part of the inner lip, from whence it 

 diminishes in breadth anteriorly. The outer lip is convex, 

 and either thickened or slightly disposed to expand ; there 



