Clare Island Survey — Acarinida. 39 3 



The following twelve species are now recorded for the first time from the 

 Britannic area : — 



Protzia eximia (Protz). Megapus nodipalpis Sic/. There. 



Sperchon undulosus Koenike. Megapus tener Sig. Thor. 



Lebertia fimbriata Sig. Thor. Unionicola gracilipalpis ( Viets). 



Oxus plantaris Sig. TJior. Aturus runcinatus (Sig. Thor). 



Atractides amplexus Koenike. Feltria circularis Piersig. 



Atractides Maglioi Koenike. Feltria Eouxi Walter. 



With the exception of Lebertia fimbriata and Unionicola gracilipalpis, these are 

 all forms inhabiting low-temperature streams and lakes (stenothermal forms) ; 

 and as very little appears to be known of the occurrence of these species in 

 Great Britain, it is extremely likely that they await discovery in the 

 highland parts of that country. 



In addition to the foregoing at least ten other species are additions to the 

 recorded water-mite fauna of Ireland. 



In the present state of our knowledge of Hydracarid distribution it is not 

 possible to apply to them the geographical groupings which have been used 

 for insects and other groups. There is no doubt that many of the species are 

 local and of restricted range, yet, generally speaking, the water-mites ate 

 remarkably widely spread animals, a characteristic which they share with other 

 fresh-water organisms. For the present, therefore, it is as well to adopt 

 Dr. Zschokke's division of the fresh-water mites into two great faunistic 

 groups— the Cosmopolitan, and the Northern and Alpine. 



The Cosmopolitan group contains a great many species of very wide 

 distribution, that mostly inhabit lowland waters of a higher temperature 

 (eurythermal forms), although a few possess a high alpine range. 



The Northern and Alpine group, on the other hand, live in waters of a 

 lower temperature (stenothermal forms), inhabiting the rapidly flowing- 

 streams of upland districts, and cold alpine and sub-alpine lakes. 



It will be seen that both of these groups are well represented in the Clare 

 Island district. 



Apart, however, from these two faunistic groups there is evidence of a 

 distinct northern element inhabiting ordinary high-temperature waters. 

 As examples we may refer to Lebertia fimbriata Sig. Thor and Ojms 

 plantaris Sig. Thor, species which have hitherto been recorded only from 

 Norway. 



There is also evidence of a distinct moor-fauna in the Clare Island 

 district, as well as in the west of Ireland generally. The more characteristic 

 members of this group are rare in or absent from localities where peat does not 



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