72 



Syn. Pleurotomaria conica, Phill. Geol. Vorks.228. 

 pi. 15./. 22. Morris, Catal. 158. 



1 HE band around the margin of this elegant shell is nar- 

 row and so hollow as to appear like two sharp ridges or 

 keels, and the furrow below produces almost a third ridge, 

 particularly in some specimens. The strife above the band 

 are numerous, elevated, slightly curved and very oblique ; 

 the strige below the band are equally numerous and ele- 

 gantly curved. 



P. striata {Helix, Min. Con. tab. 171.) has slightly con- 

 vex whorls, more distant, less oblique and stronger striae, 

 a wider and flatter band, and shorter spire, otherwise it 

 bears a strong resemblance : they both are liable to be va- 

 riegated with dark brown. 



Found in the carboniferous limestone of Bolland. 



PLEUROTOMARIA tumida. 



TAB. DCXL.— /g^. 5. 



Spec. Char. Depressed^ nearly smooth ; whorls 

 few, rounded, convex above with a slight canal 

 near the suture, very convex beneath ; umbi- 

 licus small with a sharp edge ; band mode- 

 rately broad, sunk; aperture transversely ovate. 



Syn. p. tumida, Phill. Geol. Yorks.226.pL 15. 

 /. 3. Morris, Catal. 159. 



Remarkable for the rapid increase of the whorls and the 

 slight depression in them near the suture. The specimen 

 has lost much of the shell, but what remains is of a very 

 dark colour except a white stripe below the band. Sent 

 to me from Bolland by Mr. Gilbertson. 



