23 32 Proceedings of the Royal Irish Academy. 



All of these would be found in. a typical faunal list from a western island, 

 and the absentees are perhaps more interesting. Thus I could not find 

 Hyalinia cellaria, Arion subfuscus, Zonitoides excavatus, Punctum pygmaeum, 

 Sphyradium edentuhcm, Hygromia hispidu, Helix nemoralis, nor Clav.sU.ia 

 bidentata. The precincts of the old church would probably have yielded some 

 from this list, but I was unable to spend more than a few moments at this 

 spot. One species — VaUonia pidchella, — is common by the lake-shore on 

 Caher, which did not occur to me on Inishturk, while the abundance of 

 Vitrina pellucida and Hyalinia alliaria contrasted strangely with their 

 extreme scarcity on the latter island. 



IXISHTUEK. 



This in several ways resembles Clare Island on a smaller scale, but suitable 

 habitats for mollusca are even more restricted than on the latter. Grassy 

 cliffs, such as those of Croaghmore and Knocknaveen, are absent, the majority 

 being quite precipitous and almost devoid of vegetation. Around Garranty, 

 however, some of the ridges with which the island is everywhere crossed are 

 on their northern slopes covered with a dense scrubby vegetation, which 

 includes Hazel, Holly, and Birch. It is not surprising, therefore, to find that 

 twenty-six out of the thirty-one land shells obtained by me on the island 

 occur in this neighbourhood. Ooghnalee, a vertical pipe eommunieating with 

 the inland end of a large sea-cave, yielded an interesting list of species. In 

 this cave the only specimen of Vitrina pellucida was taken. The ancient 

 graveyard was disappointing, 1 and contained nothing of interest beyond 

 Hyalinia cellaria, a colony of H nitidv.la var. helmi, and some Helix aspersa 

 with the curiously wrinkled texture met with in shells of this species 

 upon several of the other islands surveyed. 



Habitats for fresh-water species are confined to the three small lakes, some 

 boggy pools and small streams. Lough Coolaknick contains Limnaea pereger, 

 Pisidium casertanum, P. nitidv.m and P. milium; Lough Aleen, L. pereger ; and 

 Lough Xamucka, in the most exposed situation of all, contains L. pereger, 

 L. palustris, and Pisidium pusiilum, while its shore appears to be the only 

 haunt of Zonitoides nitidvs. Except in the habitats mentioned above, the island 

 is almost devoid of a mollusean fauna, consisting as it does, for the greater part, 

 of heavily glaciated ridges of Silurian rock, bare of drift, but here and there 

 thinly covered with peaty soil. Upon these inhospitable areas Limax arburum 

 — the so-called Tree Slug — is usually abundant ; Arion ater is common ; 

 while A. subfuscus, A. intermedins, Hyalinia alliaria, H. radiatula, Pyramidula 

 rotundaia and Cochlicopa Ivhrica occur sparingly. 



1 The large quantity of Bracken (Ptcris Aquilina) may account for the scarcity of shells. 



