54 



THE NON-MARINE MOLLUSCA OF ICELAND. 



By F. H. SIKES, M.A., F.L.S. 



(Read before the Society, Jan. 8th, 1913). 



The authorities on this subject are Westerlund (Synopsis Mollusc. 

 Extramarin. Scand., 1897) and Morch (Faunula Mollusc. Islandiae, 

 1868), from which it would appear that there has not been any recent 

 investigation, inasmuch as the excellent Museum at Reykjavik con- 

 tains only seven or eight species. 



Dr. Morch, whose list is almost identical with Westerlund's, 

 certainly gathered together a considerable number of records, when 

 one takes into account the barrenness of the land, and though, in a 

 recent visit, I almost literally left no stone unturned, I can only sup- 

 plement his list by three species. As they are all Pisidia, it is probable 

 that even one or two of these were found by Morch and wrongly 

 identified, a lot of water having flowed under the Pisidian bridge 

 since 1869. 



In my eleven days' voyage I practically circumnavigated the island, 

 and called in at ten fjords, afterwards spending a fortnight in the 

 interior. It seemed to me a curious fact that such results as I got are 

 almost entirely due to prospecting in the north, as at Reykjavik, and 

 from there up to the geysers, via Thingvellir, nothing except a Vitrina 

 of the land molluscs turned up. At Hafnarfjordr, however, which is 

 six miles from the capital, I found among the lava crevices Arion ater 

 and sub/uscus, and Hyalinia alliaria in some quantity. Helix aspeisa 

 seems to be non-existent; all my solicitous enquiries after it only led 

 me into wild goose chases (if one can use this expression about a 

 country where these birds are plentiful) and consequent 'bagging' of 

 A. ater, which was the nearest that my informants could get to my 

 description of aspersa. 



I was interested to find that Hdix hortemis, which has long been 

 of rather doubtful authenticity, is not only confirmed by a mouse- 

 nibbled specimen I got at Seydisfjordr, but also by a var. kleinia 

 taken by Mr. B. Sammundssen in 1896 at Drangshted. 



Though one quarter as large again as Ireland, one-eighth of Iceland 

 is under lava and one-ninth covered with glacier. When one adds to 

 this the precipitous mountains in the proportion of 15 to i of level 

 ground, it will be seen that it is not a very likely recruiting ground 

 for land and freshwater mollusca. 



According to the learned geologist, Dr. Pjeturrs, of Reykjavik, 

 Iceland is a tableland built up of basalts with intercalated beds of 

 sedimentary rock. The thickness is estimated at 12,000 to 14^000 ft., 



