39 48 Proceedings of the Royal Irish Academy. 



submergence to which the more decidedly maritime forms are subjected: 

 to this fauna belong Gamasus Kempersi, Gamasm immanis, Halolaelaps 

 alticus n. sp., Gamasolaelaps aurantiacus, Haluropoda inter rvpto. n. sp., H. 

 minor n. sp. and the oribatid mites Scutorertae bilineatiis and S. corrugatus. 



Much observation is needed with regard to the exact " zoning " of these 

 littoral forms, and there are some interesting points in their structure and 

 life-history which would repay investigation. In the species Halolaelajps 

 glabriuseulus, for instance, the ambulacra are highly modified from the 

 ordinary gamasid type, while in the allied Halolaelaps celticus, occurring 

 higher up at about high-water mark, these organs, though of si milar type, 

 are less highly specialized. Similarly in the protonymph of Cyrthydrolaelaps 

 the ambulacra are less modified than in the adult. 



It is well known that many kinds of mites are only found in ants' nests 

 where they live on friendly terms with the ants. Mr. Michael was the first 

 acarologist to study these interesting creatures (48a), and Berlese has 

 published a very useful paper (12) with descriptions of all of the known 

 myrmecophilous forms, these belong, with few exceptions, to the group 

 Gamasoidea. The district is not rich in these mites, the following species 

 occurred : — Urotachytes formica rius, UrodiseeUa philoetena, Lo.elaps montanus, 

 L. vacuus, L. styliferus n. sp., L. acutus, and the hypopial nymph of Tyroglyphus 

 Wasmanni. 



An undoubted sphagnum fauna occurs in very wet places on the 

 mountains and also in sphagnum pools on the moors, the following species may 

 be referred to in this connexion : — Crytoladaps transisalae, Paraseius serratus 

 n. sp., Seiulus minutus n. sp., Oribata sphagni, Nataspis lacustris, Kothrusglaber, 

 N. tardus, and N. monodactylus, Smarts expalpis, MicrothromJbidium valgum, 

 and others. The last two species I have found in sphagnum pools in 

 company with the ArrAenurus -~ and other water mites on the Mulranny 

 moors. 



As regards the general results obtained in the present report it may be 

 mentioned that this is apparently the first attempt to record a local fauna 

 dealing with more than one group of the Acarina in this country, or, indeed, 

 in the British Isles. It has been found necessary to define three new 

 gamasid genera and there are descriptions and figures of 22 new species 

 and 5 new varieties of the Acarina. Apart also from the extension in the 

 known range of many species at least 90 are recorded from Britain for the 

 first time, due to the scarcity of British records in the groups Gamasoidea 

 and Thromboidea, while at least 156 species were previously unrecorded 

 from Ireland. 



The classification made use of is mainly that proposed a few years ago by 



