126 Alien Molhtsca in Yorkshire. 



R. le Brockton Tomlin, M.A. Up to the present, the species 

 found are as follows : — 



From Elland : — From Wakefield : — 



Helix verinictdata juv. Miill. Helix vermiculata Miill. 



Helicella emphorca Bourgt. H . melanostoma Drap. 



H. terrestris Penn. H. nissleri Pall., 



H. maiiritanica Bourgt. Helicella pyramidata Drap. and 

 H. pyramidata Drap. varieties monozona, alba, mar- 



H. numidica Bourgt. morata, dcpressa and conica. 



H. affinior Deb. H. rhodocheila West. 



H. globuloidea Terv. H. numidica Bourgt. 



Leucochroa candidissima H . cespiHtm Drap. 



Drap. Leucochroa candidissima Drap. 



together with broken valves of non-British Anodonta and Unio, 

 and odd specimens of Cypraea annulus, the latter presumably 

 dropped on the land surface wlience the barley came. 



The general facies of the above indicates an origin from 

 Northern Africa, a conclusion which Mr. Horrell tells us is 

 partially but not fully confirmed by the plants and the beetles 

 found with them. 



Mr. J. F, Musham of Selby has drawn our attention to quite 

 a different source for alien molluscs. The Yorkshire Dyeware 

 and Chemical Co. at Selby, import from Jamaica large quantities 

 of logwood for the purpose of extracting dyes for commercial 

 use. The wood arrives in the form of large logs which are 

 unloaded from the canal extending by the works. In unloading 

 and drying the wood many animals which have been secreted 

 in the crevices of the logs make their presence known. Recently 

 living examples of a fair sized lizard, scorpion, hermit crab 

 and a large cockroach have been seen, together with numerous 

 empty shells of land and marine moUusca. Mr. R. Standen 

 of the Manchester University has indentified most of the mol- 

 lusca and Mr. J. R. le Brockton Tomlin the remainder, none 

 of which were alive when found. 



The Lucerna are characteristic of and confined to Jamaica. 

 The species found are as under : — 



Neocyclotus jamaicensis Ch. Lucerna acuta Lam. var. 



Helicina neritella Lam. L. subacuta Pfr. 



Colobo stylus red fieldianusCB. Ad. L. subsloaneana Pils. 

 Lucerna picturatus Adams. Livona pica L. 



Many. Littorina sp., indistinguish- 



L. soror Fer. able from L. littorea. 



All these are land shells except the last two, which are 

 marine. There is no question of establishing themselves as 

 all were dead when obtained. Similar importations with log- 

 wood have long been recorded for San Francisco and Germany. 



The writers would be glad to learn of any other Yorkshire 

 instances. 



NatutalisI 



