39 2 Proceedings of the Royal Irish Academy. 



The species recorded in the following list are fairly representative of the 

 Hydracarid fauna of the district, as, with some experience of the habits of the 

 species, a fairly satisfactory knowledge of this group can be obtained in a 

 comparatively short time. The ordinary methods of netting, both from boat 

 and shore, were carried out pretty thoroughly, often necessitating wading, 

 especially in the case of the small, treacherous peaty lakes, to reach the water- 

 plants amongst which these mites are mostly to be found. On account of the 

 remote nature of many of these lakes, a boat was often unobtainable, otherwise 

 a few additional species might have been found, more especially in the deep 

 tarns of the mountainous parts. 



As regards the general results of the Survey, it will be seen that thirty-one 

 genera, represented by eighty species of fresh-water mites, were collected. 

 It is satisfactory to be able to record the occurrence of four previously 

 undescribed species. These are : — 



Eylais relicta n. sp. 

 Frontipoda Carpenteri n. sp. 

 Atractides (Torrenticola) brevirostris n. sp. 

 Unionicola (Atax) rivularis n. sp. 1 



The first of these occurred in Glendalough Lake, Connemara; and I have 

 also taken immature examples in Castlebar Lake, and in the mountain tarn 

 on Croniaglaun, near Killarney, well known to British conchologists as the 

 home of the rare water-snail Limnaea involvia. The new Frontipoda is, 

 however, the most interesting species discovered during the Survey, as up to 

 the present time the genus was represented by one widely distributed form — 

 Frontipoda rnuscvlus, Muller — from which the new species is distinguished by 

 well-marked characters. It is probable that Frontipoda Carpenteri will prove 

 of distributional interest when its range in western Europe has been 

 ascertained. The Atractides adds another to the four species described since 

 the appearance of the " Tierreich " volume ten years ago. Unionicola rivularis 

 is a remarkably small species apparently inhabiting rivers ; the type specimens 

 were found in the Westport Eiver, and in the Eiver Nore in S. E. Ireland. 



A distinctive name (montanus n. var.) has been given to the interesting 

 rapid-water form of Megapus spinipes (C. L. Koch). Features of this variety 

 are the absence of swimming-hairs, and the enlarged claw-armature — modifi- 

 cations of structure to suit its usual habitat in rapid .highland streams. 



There will also be found in the following pages a reference to a second 

 nymphal form which has not been previously observed in the genus Protzia. 



1 A fifth new species, Arrhenurw Hpapilhsus, found recently outside the Clare Island district, is 

 also for convenience described in this paper (p. 39). 



