23 H Proceedings of the Royal Irish Academy. 



to show great partiality for the Mowers of Silene ncaulis (see Part 10, p. 24 and 

 Plate V). I also observed it feeding on this plant, as well as on the flowers of 

 Jarionc montann, but its customary food seemed to be sheep-droppings, or 

 decaying vegetable matter. During the long drought of 1911 A. titer was 

 frequently seen under stones in the beds of half-dried streams and under 

 clumps of Sphagnum. The effect of exposure — or perhaps it is due to the 

 action of salt water during winter storms — is well shown on many of the 

 shells living on Croaghmore, especially in the cases of Pupa anglica and 

 Clausilin bidentata (Plate II, fig. 41). Many examples of these are to be 

 found with the upper half of their shells completely bleached or eroded while 

 the lower remains in perfect condition, having been formed since the passing 

 of the previous winter. The old shells of these, and often of other species, 

 are bleached throughout. The most interesting shell living on Croaghmore 

 is, to my mind, Limnaea trunc/ittda, which swarms on the bare rock-faces 

 of the cliff and is frequently associated among the moss and other vegetation 

 with what would generally be termed " woodland " species. Excepting the 

 escarpment of Knocknaveen, the only inland sanctuaries for mollusca are the 

 small areas of native scrub on the hill-sides above L. Avullin and in the 

 valleys above Portlea, near Maum. These two localities furnished almost 

 identical lists, but no species is confined to either station. Upon the 

 northern slope of the last-mentioned valley stand the ruins of several 

 cottages. These attracted my attention for two reasons. Firstly, there were 

 many stones to turn over round about them; secondly, I wanted to see if 

 man's former habitation was reflected in the neighbouring fauna. In no case 

 was man's former presence traceable, for while Hyalinia alliaria, Arion 

 subfuscus, and other species typical of the island lived about the ruins, Limax 

 arbomm and Zonitoides excavatus — the latter a typical " anthropophobe " — 

 occupied the interior of one of the buildings, eight examples of the latter 

 occurring under a large stone near the hearth. Perhaps one of the strangest 

 groups in the fauna is that met with at the extreme western end of the island 

 where Plantago sward is the prevailing form of vegetation. During heavy 

 winter storms this portion of the island must be almost immersed in sea 

 water. Yet no less than fifteen species of mollusca have been found to live 

 in this area. The list is as follows :— - Limax arborum, Milax gugates, Agrio- 

 limax agrestis, A. laevis, Arion (iter, A. intermedins, Hyalinia alliaria, Glausilia 

 bidentata, Ancylus fluviatilis, 1 Limnaea pereger, L. palustris, Planorbis spirorbis, 

 Pisidium subtruneatum, P. cnsertanvmx, and P. personatum. 



1 The fresh- water species -occurred in the pools forming Lough-na-phuca, and in the small 

 stream which flows through some of these pools. 



