298 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



XXVII. 



NOTES ON THE LAND AND FRESH-WATER 



MOLLUSC A OF ION A. 



BY ALEX. SOMERVILLE, B.SC, F.L.S. 



[Read 24th April, 1888.] 



On the occasion of a visit to the Island of Iona, in 

 October, 1887, I devoted a short time to the investi- 

 gation of its land and fresh-water mollusca ; and 

 though I cannot claim to have exhausted the species 

 occuring on the island, it may be of interest to 

 mention that sixteen rewarded search, one being 

 aquatic, and the remainder, including three slugs, 

 terrestrial. 



The western and uninhabited side of Iona faces 

 the Atlantic, and is rocky, excepting towards the 

 middle, where there is an open bay, from which 

 stretch up sandy, grass-covered undulations. Here 

 Helix ericetorum, Mull., and Bulimus acutus (Mull.),, 

 were swarming, as they do in many similar places 

 on the West of Scotland from the Butt of Lewis to 

 the Mull of Cantyre and on the sandy Ayrshire 

 coast. On the eastern, or inhabited side of the island, 

 under stones near human dwellings, most of the 

 species met with were found ; and of these the most 

 plentiful was Helix sericea. Mull., a local though 

 widely-distributed form, so named from its epidermic 

 covering of fine white silky hairs which do not 

 easily rub off. 



The following is a list of what were obtained, 



