Clare Island Survey — Acarimda. 39 5 



As far as the present water-mite fauna of Clare Island is concerned I am 

 inclined to believe that it has survived there since the island formed part of 

 the mainland ; and that if glacial conditions did occur subsequent to the 

 separation of the island they were probably not as severe as is generally 

 supposed to have been the ease. The occurrence of even a short summer — 

 such, for example, as exists in Lapland at the present clay — when permanent 

 fresh-water pools were formed in sheltered places in the glacial clays, would 

 probably be sufficient to have preserved a Hydracarid fauna on the island. 



Sub-Order HYDRACARINA. 



Fain. LIMNOCHAKIDAE. 



Sub-fam. Limnocharinae. 



Limnochares aquatica (L.). 



Sraheens Lough, Achill ; common in the shallow margin of Lough Cahasy, 

 Louisburgh ; Garranbawn Lough, Ballinakill. 



Sub-fam. Eyla'i'nae. 

 Eylais discreta Koenike. (Plate I., fig. 1.) 



Castlebar Lake ; lake near Westport ; Prospect Lough near Belclare ; 

 Lough Namucka near Louisburgh. 



This fine species, one of the giants of the genus Eylais, occurred abundantly 

 in the above localities in the southern part of the district. 



Var. stagnalis Halbt. (Plate I., fig. 2 a, b.) 

 Eylais infundibulifera var. stagnalis (6). 



The structure of the eye-plate shows considerable variation. The great 

 majority of the Clare Island district specimens differ from the typical 

 form, as this is figured by Koenike (12, etc.), in having a chitinous muscle- 

 attachment projecting well beyond the front margin of the eye-plate in 

 the middle line (PI. I., fig. 2). The concavity of the hinder margin is 

 deeper, and is usually rounded at the apex. This form agrees with the Eylais 

 which I described under the name E. infundibulifera var. stagnalis some years 

 ago. After a careful examination of the abundant material now in hand, there 

 is little doubt that this form should be referred to a variety of Eylais discreta 

 Koenike. 



The palps in these specimens are decidedly shorter and stouter than in 

 E. infundibtdifera. The second segment is broad with nine to ten stout spines 

 along the inner distal margin ; those in the middle are pectinated. In the 



