236 The Irish Naturalist, [Sept., 



And now Mr. Welch makes the further interesting discovery 

 of the shell in Ireland, and he has ascertained for me that 

 three firms import Baltic timber at Coleraine, and that a con- 

 siderable amount was used for the Bann-mouth Extension 

 works. 



In 1 883- 1 884 I did a good deal of collecting in this locality, 

 and I fancy I should have remarked the shell if I had come 

 across it, as it was then an unknown form. 



Such, briefly, is the history of this species, and the following 

 points are suggested : — 



Had the shell come from Norwa}^ Sweden, or Prussia, it is ' 

 likely that it would have been discovered ere now by some of 

 the keen investigators of those countries, but it is not so 

 likely that conchologists have wandered along the low-lying 

 shores of Russia and Finland, which shores, from personal 

 knowledge, I can testify to being extremely desolate and 

 difiicult to traverse. These shores have large inlets and 

 brackish marshes where the timber is stored previous to 

 shipment, and I imagine it is from these places that the shell 

 comes. Of course it may be indigenous to the British Isles 

 but in that case it is difficult to account for its having escaped 

 the notice of the numerous conchologists, who for the past 

 forty 3^ears have made many of its habitats their favourite 

 hunting-grounds ; the Staffordshire canal and the mouth of 

 the Bann being the only habitats that have been little worked. 



In my " Collector's Manual of British Land and Freshwater 

 Shells " I have figured the shell and discussed its alleged 

 identity with the West Indian species, but even if this 

 identity turns out a certainty, another question arises. Is it 

 indigenous to the West Indies, or was it imported there in 

 Baltic timber ? 



Of course it remains to be seen whether it exists on the 

 shores of the Baltic, for it must be remembered that its 

 Existence there is merely based upon a hypothesis, which, 

 however, seems probable. 



