37 12 Proceedings of the Royal Irish Academy. 



Summary. 



The Clare Island Survey has collected thirty-three species of Water-bears, 

 besides some distinct varieties which may eventually be elevated to the rank 

 of species. 



The examination of the Irish Water-bear fauna will be instructive in so 

 far as it brings to light some correspondence with the faunas of other 

 countries, as well as peculiarities of its own. 



It is natural to compare the Irish Arctiscoida first with those of Scotland, 

 as the countries are so near, and so similar in physical features and climate. 

 Scotland has fifty species of Water-bears, and Ireland has thirty-three. 

 Scotland has been worked for a longer time and over a wider area. As the 

 Irish list was compiled in one small corner of the island, the number of species 

 may be considered very fair as a beginning. 



The amount of difference between these two adjacent countries is con- 

 siderable. There are twenty-two species common to the two countries, leaving 

 twenty-eight Scottish species which are unknown in Ireland, and eleven Irish 

 species which have not been recorded for Scotland. The difference is reduced 

 by the recording here of three species previously known in Scotland, but not 

 i*ecognized as distinct. 



Among the eleven species not found in the Scottish list there are five 

 which are described as new species. Macrobiotus riehtersii and M. scabrosus 

 are here recorded for Scotland, so that there are only three species which 

 at present appear to be peculiar to Ireland (Eehiniscus militaris, E. columinis, 

 and Macrobiotus hibemicus). 



Arctic Species in Ireland. — It was expected that some Arctic species might 

 appear on the Irish mountains, as they are known to occur in Scotland. 

 Sixteen species, or nearly half of the Irish list, are common to Ireland and 

 the Arctic Eegion ; but the majority of these are cosmopolitan species. The 

 following half-dozen species are at present limited in their known range to 

 the north temperate and Arctic regions : — Eehiniscus crassus, Macrobiotus 

 crenulatus, M. virgatus, M. arcticus (also in . the Antarctic), M. sehaudinni, 

 Biplmscon angustatum, 



Canadian Species in Ireland. — An interesting feature of the Irish list is 

 the occurrence of three Water-bears which were recently discovered in Canada, 

 and which were hitherto unknown in Europe : — Eehiniscus intermedins, 

 Macrobiotus occidentalis, and M. virgatus. The two first have now been found 

 in Sweden by Herr Thulin, though I am not aware that the records have been 

 published. E. intermedins is also on record for Australia and Hawaii ; but it 

 is very likely that the three forms will be eventually recognized as distinct 



