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XXII. 



THE SLUGS OF IRELAND. By R. F. SCHARFF, Ph. D., B. Sc. 

 (Plates LVI. and LVII.) 



{Abstract of Paper read February 18, 1891, and published in the Scientific Transac- 

 tions, EoYAL Dublin Society, Vol. IV., Fart X., page 513, with Plates Ivi. 

 and Ivii.) 



A MORE minute description of the various species of slugs living in 

 Ireland is not only of anatomical interest, but of much importance 

 to those engaged in tracing the geographical distribution of 

 animals. 



Many problems with regard to the origin of our native Fauna 

 have still to be solved. For instance, the question at what particu- 

 lar geological period Ireland was united with England and the 

 Continent of Europe is one which can only be satisfactorily 

 answered from a careful study and comparison of the respective 

 Fauna and Flora of these countries. 



Some of the Irish animals and plants may have been carried 

 across the sea from England or France, by winds or marine cur- 

 rents, and have become established in time, and it is not therefore 

 always safe to draw conclusions from all groups of the animal and 

 vegetable kingdom. Slugs, however, are not likely to be carried 

 about by aerial currents, and as they and their eggs are killed by 

 immersion in sea- water, it seems only reasonable to conclude that 

 any species now existing in Ireland, if it be proved to be identical 

 in structure v;ith a Continental form, has found its way across by 

 means of a land passage. 



There are thirteen species of slugs in Ireland, all of which, 

 with one exception, are also found in Grreat Britain. This 

 one species, viz. Geomalacus maculosus, is not only absent from 

 Great Britain, but also from the whole of Central and Northern 

 Europe. It appears again in Northern Spain, in the province of 

 Asturias. In Ireland it has hitherto only been found in the coun- 

 ties of Kerry and Cork, which two counties have likewise yielded 

 many interesting Southern plants. 



