€0 ZOOLOGY. 



shrimp-like Schizopod, Mysis relicta, of Lough Neagh, one of the most in- 

 teresting of Irish animals. Inhabiting freshwaters in Ireland, Sweden, 

 Norway, Russia and North America, it nevertheless belongs to a marine 

 genus, and is st ill living in the Baltic ; its distribution indicates, therefore, 

 a former extension of the sea over a great part of north-western Europe. 

 No detailed reference to marine Crustacea is possible in this sketch, but 

 several forms of much interest have been dredged from deep water off the 

 west coast. 



Fig. 6. — Mysis relicta, Lough Neagh. Twice natural size. 



Two south European Earthworms {Allolobophora Georgii and A. vcneta) 



have been discovered in Ireland in recent years. Of 



-,., * the interesting but obscure group of the Land Plan- 



arians, m addition to the common European and 



British Rhynchodenius ierrestris, Ireland possesses a 



species — R. Scharjfi — which has not yet been found elsewhere. 



Noteworthy among Irish shore-hunting Echinoderms is the Purple Sea- 

 urchin {Strongylocentotus lividus) which may be 



„ , . , found in numbers along the west coast northwards to 



Echinoderms. t-. i 4^u *. i.u u j 



Donegal, the specimens resting in the cup-shaped 



hollows that they excavate in the rocks. This 



species ranges in Ireland much farther north than elsewhere, for in Great 



Britain it is found only in the south-west, and on the continental coasts from 



France southwards. In the deep water to the west, northern and southern 



forms mingle in the Irish marine area.t Among the northern species the 



handsome scarlet sea-cucumber Holothiiria trenmla and the starfish Pontas- 



ter tenuis pinis are noteworthy. The steep submarine slope beyond the lOO 



fathom line, where such specimens are dredged, suggests irresistibly the 



western shore of an old continent stretching from north to south. 



* H. Friend, Papers on Irish Earthworms. Irish Nat., vols, i.-iv., 1892-5. R. F. Scharff. 

 •" The Irish Land Planarians." Irish Nat., vol. i.x., 1900. 



t A. C. Haddon and W. S. Green. " Second Report on the Marine Fauna of S.W. Ireland." 

 Proc. R. I. Acad. (3), vol. i., 1889. 



