104 

 Turbo sexdentatus. Mont. tab. 19^. fig. 8. 



Shell somewhat smaller than the last and of a more 

 conical shape, with the volutions more rounded 

 and better defined ; and may be readily known by 

 the two distinct teeth on the surface between the 

 two lips on the upper part of the aperture, the 

 right tooth much the larger. 



Distinguished and sent to us by Mr. J. Alder, from 

 Newcastle ; and by Mr. Bean from Scarborough. 



85. VERTIGO palustris. Shell oval, ventricose : 

 aperture with eight unequal teeth, three of which 

 are superior and between the lips of the peritreme. 



Vertigo palustris. Leach, Mollusc. p. 128. t. S.f. 10. 

 Pupa antivertigo. Drap. p. 60. t. S.f. 3%, 33. 



b. Aperture with an additional tubercle. 



Shell smaller than the last, of a deep chestnut-brown 

 colour, with the margin of the aperture whitish : 

 teeth three above and three below and one on each 

 side, and often a ninth tubercular tooth. 



It may easily be distinguished by the three very dis- 

 cernible white teeth of unequal size within the 

 upper and truncated part of the aperture ; whereas 

 there is only a single central one apparently visible 



