246 PNEUMONOBRANCHIATA. 



Dr. Drummond and Mr. Hyndman, the largest is 

 5J lines in length and 3J in breadth; volutions 4, 

 the largest enveloping the other three, none of which 

 are visible in the profile of the shell ; aperture very 

 large, wide at the base (showing the columella 

 throughout its entire length), and extending to the 

 apex; margin reflected only where it joins the 

 pillar. 



" Shell polished, extremely thin, of a pale amber- 

 colour, with coarse longitudinal striae. It approaches 

 L. glutinosus more nearly than any other species ; 

 but in consequence of the aperture extending to the 

 apex, has, at a cursory view, a greater resemblance 

 to Bulla akera than to any other British shell, 

 their similarity being rendered still more striking by 

 the columella having the same appearance in both 

 species. 



" The above description was read to the Linnaean 

 Society, April ] 5th, 1834. To the present time ( Sep- 

 tember, 1839), I have not heard of the species being 

 obtained in any other locality in Ireland. With 

 Robert Ball, Esq., of Dublin, I visited the lake or 

 tarn on Cromaglaun mountain, in June, 1834, when 

 we procured only a few small specimens ; the time, 

 however, was unfavourable for seeing the object of 

 our search to any advantage, being at a very early 

 hour of the morning, before the warmth of the sun 

 had tempted any of them to leave the bottom of the 

 lake or adjoining rivulet. 



" This Mollusk probably belongs to Nilson's genus 

 Amphipeplea." 



I am indebted to Mr. Ball for the specimen figured ; 

 it is evidently a very distinct species. 



