CERITHIUM. 



Costatuin, 196. 



xlv 



Turbiforme, 193. 

 Tuberculare, 193, /. 8, 

 Reticulatum, 193. 



narrow longitudinal ribs, which are about one third of 

 the breadth of the interstices, and a single raised 

 spiral rib situated a little below the middle of each 

 whorl ; two additional rather indistinct lower ones on 

 the body whorl, which occupies one third the length of 

 the shell, ^...breadth two fifths of length. Guernsey. 

 This most beautiful species, from the upper portion of 

 the whorls being flattened, seems in a fine specimen to 

 have the ribs tuberculated at their summit, or when 

 rubbed, even to form a spiral band there. The aperture 

 is small and squarish ; there is no umbilicus but in per- 

 fect specimens, a slight umbilical groove and a very in- 

 distinct plait on the eolumella, but not the contracted 

 mouth of Odostomia. 



(j) TURBO ASCARIS, Tart. Die. 217. Extremely 

 slender, tapering to an exceedingly fine point, milk 

 white, semitransparent ; whorls 7 or 8, rounded and 

 well defined by a deep impression, each with 4 or 5 

 regular equidistant and rather deep spiral grooves ; 

 aperture suborbicular, the inner lip a little reflected. 

 Breadth a fourth of the length, which is not the tenth 

 of an inch. Seafield Ireland. Rare. 



