140 pyramidellidjE. 



slightly channelled, and somewhat oblique : mouth irregularly 

 oblong, owing to the inflexion and curvature of the outer lip ; 

 it is acute-angled above (but not so sharply as in 0. plicata), 

 and decidedly expanded below ; its length equals a third of 

 the whole spire : outer lip remarkably flexuous, retreating at 

 the upper corner of the mouth, where it forms a deep sinus, 

 and inflected in the middle, so as to contract the mouth on that 

 side : inner lip as in the last species ; the lower part, however, 

 is more reflected and straight in the present species : umbilicus 

 small and narrow: tooth — or rather an oblique fold — retired 

 and inconspicuous, although always present : operculum re- 

 markably thin, light-horncolour, narrow, and obliquely striated. 

 (This description of the operculum is taken from Mr. Clark's 

 account.) L. 0-15. B. 0-0625. 



Habitat : Coralline and deep-sea zones, throughout 

 the British seas, from 10 to 85 f. ; not common. I have 

 noted 26 localities. Coralline Crag, Sutton (S. Wood); 

 post-glacial shell-banks near Drontheim, 60-80 feet 

 (Sars) . It has been found living at Drobak in Chris- 

 tianiafiord, in 50 f., and at the Loffoden Isles, in 50- 

 100 f., by Sars, at Kullen in South Sweden by Orsted 

 (and named by Loven Turbonilla obliqua), at Gotten- 

 burg, in 16 f., by Malm (who described it as T. War- 

 renii), and in Brittany by Cailliaud and Tasle. 



The incised revolving lines round the lower part of 

 each whorl readily serve to recognize this species in 

 comparison with any of the foregoing. 



It is in all probability the Turbo divisus of Adams, 

 with rather more doubt Pyramis nivosus of Brown, and 

 unquestionably Turbonella transparens of Leach, if re- 

 liance is to be placed on the authenticity of his type in 

 the British Museum. But, in his ' Mollusca of Great 

 Britain/ the last-named species is described as " very 

 smooth/' and the few other characters there given are 

 common to all its congeners of the present section. 



