lo The Irish Nahiralist. [January, 



birds being carriers of land-shells is so remote a contingency 

 that it need scarcely be looked upon as entering within the 

 range of possibilities. We might therefore consider the 

 natives of the Great Skellig to be the descendants of species 

 which walked or crawled to it on dry land long j^ears ago 

 when the rock was the summit of a mountain standing on a 

 plain which formed part of the mainland. One unfortunate 

 circumstance, however, deprives the animal inhabitants of 

 this proud position. Monks formerly lived on the island, and 

 built a rough stone chapel on the summit with steps leading 

 to it, and it is possible that there was in ancient times free 

 intercourse with the mainland, from which some of the species 

 may then have been accidentally introduced. In more 

 recent years a lighthouse has been built on the island, and an 

 occasional supply of vegetables sent to the keeper might 

 contain a species or two which possibh' could propagate and 

 leave a numerous progeny on the rock. 



But the moUuscan fauna contains some species characteristic 

 of uncultivated ground, which certainly would never take 

 shelter among vegetables or near houses, so that I think they 

 cannot have been accidentall}^ introduced. Indeed there are 

 but few species in the list which might owe their existence on 

 the rock to accidental introduction. Such are Ao-riolimax 

 agrestis, Hyalijiia ccllarla, Helix rottcndata, and Pupa 

 cylindracca. 



For samples of specimens from the island, I am specially 

 indebted to the Rev. A. H. Delap, wdio on frequent visits 

 never omitted to bring back with him a little box full of slugs 

 and snails. But other people not less interested in natural 

 science have visited the island. Thus a number of species 

 were recently collected by Prof Boyd Dawkins, and duly 

 recorded by Mr. R. Standen in the Jo2t7ii. of Coiichology (vol. 

 viii., 1897). Mr. R. Welch, of Belfast, kindly supplied me 

 with a list of the shells collected by Mr. S. K. Kirker and by 

 the Rev. H. W. Lett in 1S97. We have, therefore, probably got 

 together a fairly complete list of all the species found on the 

 island, especially when we take into account the list published 

 by Mr. Cockerell ^ of Mr. Delap's earlier captures. 



' Zoologist (3rd sen), vol. x., 1886. 



