496 TROCHID^. 



shining livid, or olivaceous white (assuming a rather more 

 bluish cast toward the apex), adorned longitudinally with 

 distant angular spots and intermediate flexuous lines of 

 fawn-colour, the latter of which are somewhat interrupted, 

 and evince a disposition towards a spiral arrangement like- 

 wise. These markings are irregularly continued upon the 

 convex and extremely prominent basal belt, which is rather 

 broader than is usual in this species ; the inferior surface of 

 the shell displays four or five distant articulated bands of 

 fawn-colour and livid white, upon a ground of paler fawn. 

 Excepting two or three grooves around the imperforated 

 axis, a few indistinct spiral strire upon the base, and 

 about two profound stria? upon the second volution, the 

 entire shell is smooth. The eight nearly flat and greatly 

 shelving whorls, which increase rather slowly in length, are 

 somewhat narrow, the height not being one half the width 

 of even the superior suture, and terminate in a rather acute 

 apex, that is not distinctly granulated, but when highly 

 magnified appears punctulate (possibly from abrasion of 

 the surface). The base is abruptly compressed, nearly 

 flat, and angulated at the circumference. The aperture is 

 rhomboidal, much broader than long, occupies about two- 

 sevenths of the entire length of the shell, and about half 

 the basal diameter. The outer lip, which is simple and 

 acute, recedes moderately at the base. The pillar-lip is 

 rather short, oblique, slightly curved, and a little tortuous. 



The breadth at the base, which is scarcely exceeded by 

 the length of the axis, is just one-third of an inch. 



Independently of the difference of colouring, an essential 

 character in the Trochi, the smooth variety of zizypliinus 

 does not present a simply conical figure, but has its whorls 

 more convex, and its lateral outline more arcuated. 



This species is a southern form, common in the Medi- 



