286 MOLLUSCA. 



Geiuis Helix. 

 H. aspersa, Mull. 



Although distributed over the four quarters of the island, this Helix is 

 less generally met with than several other common species. In a well- 

 cultivated and moderately-wooded district near Belfast, stretching along 

 the base of the mountains where chalk chiefly prevails, presenting different 

 soils, especially clay and alluvium, and rising to an elevation of 500 feet 

 above the sea, it is never found. Mr. Edward Waller, who has success- 

 fully investigated the MoUusca about Annahoe, County Tyrone, states 

 that the H. aspersa is unknown thei-e. It seems partial to the vicinity of 

 the sea ; so much so, that about Ballantrae, in Ayrshire, Scotland, I 

 have remarked numbers of them on rocks subjected to the spray of the 

 waves, which had bleached the portion of the shell thus exposed as white 

 as it usually becomes in the progress of decay, although the animal in- 

 habitants were all in the highest vigour. In the crannies of the ruined 

 castles, which, like Dunluce, are based upon the summits of some of the 

 highest cliffs washed by the sea in the North of Ireland, the H. aspersa is 

 abundant. 



In one instance which may be mentioned, differences of rocks, soil, or 

 shelter will not explain the absence of this species from particular local- 

 ities. During a forenoon's walk on the marine sand-hills of Portrush and 

 Macgilligan (County of Londonderry), which are only a few miles apart, 

 and present in every i-espect precisely the same appearance, I found the 

 M. aspersa abundant at the former, but at the latter wanting, and here 

 the sand-hills are much more extensive than at Portrush. At the nearest 

 sand-hills, again, on the coast to the east of the latter, and only a few 

 miles distant, I did not during a short visit find the 11. aspersa ; and here 

 Helix virf/ata, which is not found at the other two localities, appeared, 

 and took the place of //. ericetorum, which is common to them ; here too, 

 and at Portrush, BuUmus acntus was present, though not so at Mac- 

 gilligan. On the 8th of June I once observed the //. aspersa in coitu, and 

 with the spicula adhering (see Montagu in Test. Brit.) ; — these are half 

 an inch in length, hollow, and widen considerably to the base. 



In the Magazine of Natural History, vol. v. p. 490, Mr. Denson states 

 that in severe winters the H. aspersa is, in the old Botanic Garden at Bury 

 St. Edmunds, eaten in quantity by the Norway rat ; a fact of which I 

 some years ago had circumstantial evidence, in the broken shells lying 

 about the enti-ance to this animal's abode among heaps of stones in the 

 Horticultural Society's Garden, at Chiswick, London.* 



* Helix Pomatia, Linn. The following observations of Professor W. H. 

 Harvey, communicated in a letter to me in January, 1834, include all that 

 need be said of this shell. " Dr. Turton, in his Conchological Dictionary, states 

 that this species is mentioned by Dr. Rutty in his Natural History of the County 

 of Dublin, as not uncommon in his time. On referring to Dr. Rutty's work, I 

 cannot find any such assertion. At p. 379, vol. i., he certainly admits it in the 

 following terms : ' Cochlea duplex primo terrestris, the terrestrial snail, and par- 

 ticularly the house snail, which is thus distinguished by Lister; Cochlea cinerea 

 maxima edulis, cujus os operculo crasso gypseo per hyemem clauditur :' and then 

 goes on to tell of its uses as food, the manner of cooking it, &c., but not one word 

 about its habitat." 



The II. Pomatia has of late years been introduced from England to different 

 localities in Ireland, as Dalkey Island, off the Dublin coast, Youghal, &c. In the 

 autumn of 18'34 I turned out a few individuals of this species and of Cyclostoma 

 elegans on the chalk in the neighbourhood of Belfast, but they have not increased ; 



