LAND AND FRESHWATER MOLLUSCS OF INNER HEBRIDES 25 



pigmented and belong to or come near the form cancellata, while 

 those from Innis Kenneth are paler and approach fasciata. Many 

 specimens from the ruins of lona have a thin, opaque calcareous 

 deposit on the shells. 



Helix nemoralis. — Common on damp basalt cliffs with a northerly 

 exposure on Innis Kenneth, less so on drier cliffs facing west and in 

 walls on Ulva. All our specimens are banded, but the number of 

 the bands varies. So many colour-forms have been described that 

 it is perhaps best not to particularise further. 



Acaiitlmmla lamellata. — A single specimen of this minute, 

 characteristically British species was found among dead leaves in a 

 hazel-coppice on Ulva. 



Helicella itala i^ = ericetorinii). — Not uncommon under stones on 

 sandy soil on lona and Innis Kenneth. Our specimens exhibit 

 great variation in coloration, and shells corresponding to the forms 

 letitiginosa, leiicozona and alba, as well as the forma typica can be 

 distinguished. We did not find any of the higher type {instabilis) 

 recorded by Jeffreys from lona. 



Cochlicopa litbrica. — On Ulva and Eorsa, scarce, under stones. 



Pupa umbilicafa. — Very common among the ruins on lona, not 

 so abundant elsewhere. Scarce, under stones, on Ulva. 



Balea perversa. — Abundant on hazels and birches in wet weather 

 on Ulva. 



Claicsilia bidentata. — My remarks on P. icnibilicata apply also to 

 this species. 



Ancylus fluviatilis. — Small specimens of this species are not 

 uncommon with L. peregra, etc., in the small hill-streams of Ulva. 

 Although I refer the species here to Ancylus for the sake of 

 uniformity in nomenclature, I agree with those malacologists who 

 regard it as generically distinct under the name Ancylastrum. 



Lim?Z(za peregra. — This is perhaps the. most widely distributed 

 and the most plastic of the European freshwater molluscs. In- 

 numerable phases have been given specific names on the continent, 

 and my recent experience in Europe makes me a little doubtful 

 whether such Asiatic forms as Z. gedrosiana are really distinct. 

 Even in the small area dealt with in this paper, no less than four 

 " forms " can be distinguished, for two of which names are available. 

 In the little hill-tarn, Loch Pot-I, as it is usually called, on the Ross 

 of Mull, the small, short-spired phase called Gulnaria lacustris by 

 Leach occurs in abundance, while in the springs on Innis Kenneth 

 typical examples of Jeffreys' maritinia were found. The latter is so 

 distinct that I am inclined to regard it provisionally as specifically 

 distinct, but I hope on another occasion to discuss some of the 

 121 AND 122 D 



