39 38 



Proceedings of the Royal Irish Academy. 



published last year by Dr. Koenike. Perhaps the most notable innovation 

 found in Dr. Koenike's arrangement is the inclusion of the genus Sperchon in 

 Limnocharidae — the recent discovery of the larval form proving its affinity 

 with that family (13). 



In connexion with the Clare Island Survey it may be of interest to indicate 

 here a few species of Hydracarina which, judging by their known range, are 

 not unlikely to prove characteristic of the west central as opposed to the east 

 central parts of Ireland. 



In the first column of the following list are recorded the species which 

 have been found in the west (counties Mayo and Galway) which would appear 

 to be absent from the east (counties Dublin and TVicklow). The second 

 column contains eastern species. 



A number of evidently widely spread forms are omitted from the lists, as 

 their discovery in both districts is probably only a matter of time. It should 

 also be pointed out that the east has been more thoroughly searched for these 

 creatures, although little is known of the fauna of the Wicklow lakes. 



At the present time we do not know enough concerning the local distri- 

 bution of the fresh-water mites to endeavour to account for their absence 

 from the districts in question. "With regard, however, to the western forms it 

 will be seen that they are largely denizens of lakes and peat-moors, and, as has 

 already been mentioned, some of these forms apparently belong to a 

 Scandinavian or northern element in our fauna (page 3). 



Those species marked with an asterisk have not been previously recorded 

 from the Britannic area. 



West. 



Eylais Koenikei Hallt. 



Eylais celtica Halbt. 



Eylais relicta Halbt. 

 *Hydryphantes placationis Thon. 



Thyas vigilans Koenike. 

 *Sperchon undulosus Koenike. 

 *Lebertia fimbriata Sig. Thor. 



Frontipoda Carpenteri nor. sp. 

 *Oxus plantaris Sig. Thor. 



East. 



Eylais hamata Koenike. 



Eylais undulosus Koenike. 

 *Panisus torrent icolus Pier sig} 



Hydrarachna maculifera Piersig. 

 *Sperchon tenuabilis Koenike.' 

 *Sperchon papillosus Sig. Thor.' 

 *Sperchon mirus Koenike.* (variety). 

 *Atractides connexus Koenike. 



Acercus latipes (0. F. Mull.). 



1 Stream in the Devil's Glen, county AVicklow, in moss on submerged stones. 

 - Under stones in the River Dodder, county Dublin. 



3 and J Found in stream (''back drain ") running between "levels" of the Grand Canal near 

 Clondalkin, county Dublin. 



