igto. Kkw. — Animah of South-Wcsieui Ireland. 65 



silted up ; and the}- were oiteii monopolised by a small crusta- 

 cean, a ver}' odd creature, of which the sexes were remarkably 

 unlike, the male having a square head and large mandibles. 

 This animal was, as Dr. W. T. Caiman informs me, Gnathia 

 inaxilJaris, or a species very near that : it was living here in 

 more or less definite channels in the silt with which the 

 fissures were tilled ; and one may inquire perhaps, since the 

 use of the male's mandibles is said to be unknown, whether 

 they are emploved in the formation of the channels which 

 seemed to be used b}' the creatures in common. No trace of 

 Obisijwi viaritimum was found at this place ; h\\\. perhaps it 

 might occur, in more completely marine conditions, less near 

 the head of the bay? 



Accordingly on August iSth I set out along the road which 

 goes under Mucksna, by the townlands of Killaha, and so to 

 Dawros Point, whence for two miles or more it runs close to 

 the bay almost on the shore itself; and hereabout, on the 

 rather flat shore behind Brennel Island, Obisimn ma7-ifim7cm 

 was found at last.' It was [^living in some plent}^ in half 

 gregarious fashion, under large stones more or less embedded 

 in moderately moist gritt}' mud — never under unstable ones 

 or under those lying in a bed saturated with water — and on 

 that part of the shore inhabited by Littorina rudis and Paht- 

 destrina stagnalis, that is to say between the region of densely 

 seaweed-covered rocks and that of Juncus and Thrift. The 

 stones themselves were w4th or without small growths of sea- 

 weed, and they would doubtless be submerged at every tide. 

 On turning them over, one saw the Obisium, and often several, 

 seated on the moist under-surface of the stones, w^here from 

 their odd figure and from being deeply coloured and intensely 

 glossy they were striking and conspicuous objects ; on the 

 same surfaces one saw, in almost every case, vast herds of the 

 small bluish CoUembolan Anurida maritima^ and generally 

 also, slowly moving about, a few individuals of the white- 

 shelled mollusc Ovatdla bidentaia^ and, running about rather 

 rapidly in all directions, good numbers of the little yellowish 

 carabid-beetle Aepiis Robifiii'^; sometimes, moreover, small 

 blackish staphylinid-beetles jWcralymma brevipomc and Horna- 

 lata halobredha were present ; and of other creatures there 



^ Irish Naf., xviii. (1909), 249. 



2 For the name of this beetle, and of the others mentioned in these 

 notes, I am indebted to Mr. J. N. Halbert. 



