110 Pmcecdings of the linijul Iris/i Academij. 



examined tliiee species were found only in the two lowest zones^namely, 

 Ilalolaelaps fflabriifscnlus, Ilijdrogainasits litloralis, and EiqwdcH varicf/atus 

 \'m: halophilus nov. ; the adnlt of Cyrthydrolaelaps hirtiis Berlese was found 

 in these zones, though its nyniphal form is abundant on the higher part of the 

 shore. No doubt these species, as well as others in the list, will be found 

 to have a wider range when additional localities have been examined. 



As already stated, these zonings are tlie result of observations carried out 

 on the stretch of limestone rocks at Malahide. At Ardfry the shore is not 

 rocky, at least in the localities examined ; there tiie species were found chiefly 

 under embedded stones in places where the botanical zones are present. Tlie 

 unmarked species are such as were found amongst stones anil decaying 

 seaweeds, or in estuaries, where the zones arc more or less obliterated. Some 

 esluarine species occurring on muddy Hats are also found on the Orange 

 Lichen zone of the open seashore. 



Less attention was given to the Halacaridae, or marine mites, than to the 

 terrestrial families ; only the species noted on the rocky shore at Malahide 

 are mentioned. Of these, Ayavc hnvi]mlpiii 'I'rouess. occurred in a small pool 

 in the Pelvetia zone (July, 1917); it does not seem to have been recorded 

 from liritish shores, tliough it is known to occur on the French coast of the 

 Knglisli Channel. The single representative of the Hydrachnidao, or fresh- 

 water miles, found during our shore work is a widely spread form, Eylais 

 fumiala Kuenike : a few s|)ecinicns occurred in fresh and brackish pools in 

 the bed of the Hroadnicadnw Water in the Malahide Estuary. These two 

 families arc included only at the end of the zonal list. 



As regards the systematic result of our work, seventy-seven species of 

 iutcrtidal Acarina arc i-ocorded in lliis paper, and they are distributed 

 in the following groups: — Gamasoidea, 28 species; Oribatoidea, 17 species; 

 Sarcoploidea, 2 sjiccies ; Trombidoidca, .'30 species. It is necessary to describe 

 a new genus (Thinoseiu.s), twelve new species, and three new varieties of 

 known species. In order to make the list as complete as possible, such 

 S|>ecie9 as liave l)ecn found in other loc;ilities besides Malahide and Ardfry, 

 reconled or otherwise, are included, notably tho-se found during the recent 

 Clare Island Survey (25). It is anticipated that at some future date an 

 account of tlio intcrlidal fauna of the Malahide and Ardfry areas from the 

 purely ecological point of view will be publisheil. 



It is with pleasure I acknowledge my indebti-diicss t<> "ui leading Kuropuan 

 Acarologist, Dr. A. I3erle.se, of Florence, who has given me most vahuible help 

 in the identification of new and little known forms. 



A »nmpleU> set of the new forms deseril^ed in this paper is deposited in 

 the National Museum, Dublin. 



