UNDOUBTED TERTIAEY SPECIES. 197 



less convex whorls, and the absence of revolvmg ridges, or lines, excepting 

 on the body-volution, and the one just below and above the suture. As 

 in that form, its apical whorls are smooth. The only good specimen of it 

 in the collection is smaller than the average size of those of the last, and 

 probably a young shell. I am now of the opinion that it is most probably 

 only a variety of that shell ; but it may be distinct. 

 Locality and position. — Same as last. 



