ZOOLOGY 



57 



The other point of interest is furnished by the Irish freshwater fishes. 

 There are distinct species or races — such as the Gillaroo Trout {Salvia 

 stoviachicus) of Lough Neagh and the Shannon and Connemara lakes ; 

 Cole's Charr (5. Colci) confined to Lough Eask, County Donegal, and 

 Lough Dan, County Wicklow ; and the PoUan {Coregonus pollan) of Lough 

 Neagh and Lough Erne* — which, though only found in Ireland, are closely 

 related to forms inhabiting the freshwaters of Great Britain. An ancient 

 freshwater home for the ancestors of these allied fishes may probably be 

 looked for in a former lake and river valley occupying the bed of the present 

 Irish Sea. 



INVERTEBRATES. 



In this brief sketch it is only possible to indicate a few of the more 

 interesting features of the Irish invertebrate animals, as illustrated by some 

 of the groups that have received a fair amount of attention from naturalists. 



Fig. 2. — The Kerry Spotted Slug {Geonialaciis maciilosits) 

 Natural size. — From ScharfF, Irisli Nat. vol. \ii. 



The most characteristic member of the ancient Lusitanian fauna is the 



Spotted Slug {Geomalacus niaculosiis) which inhabits 



a considerable tract of country in western Kerry and 



Molluscs.! Cork, notably in the neighbourhood of Kenmare. It 



is found nowhere else in the British Islands, and is 



quite unknown in Central Europe, but reappears in north-western Spain 



and Portugal. Its range, therefore, recalls that of the characteristic western 



Irish plants. The colours of this interesting slug harmonise closely with the 



lichen-covered rocks on which it lives ; in dry weather it retires into deep 



crevices. 



Several other Irish molluscs, though less restricted in their range than 

 Geomalacus, clearly belong to the same faunistic group. That prettily- 

 marked Snail Helix pisana, for example, which inhabits the eastern coast of 

 Ireland from Rush, County Dublin, northwards to Drogheda, and reappears 

 on the opposite shore of St. George's Channel in South Wales and Cornwall, 



* W. Thompson. " The Natural History of Ireland." London, 1849-56. 

 t R. F. Scharff. " The Irish Land and Freshwater Mollusca." Irish Nat., vol. i., 1892. 

 A. R. Nichols. " A List of the Marine Mollusca of Ireland." Proc. R. I, Acad. (3), vol. v., 1900. 



