THE OCCURRENCE OF HELIX CANTIANA IN SCOTLAND 169 



ON THE OCCURRENCE OF HELIX CANTIANA 



IN SCOTLAND. 



By Robert Dunlop. 



According to Mr John W. Taylor's new work on the Land 

 and Fresh-water Shells of the British Isles, Helix cmittana 

 has never been recorded from Scotland, except as introduced 

 by Mr W, Baillie from England to Brora, Sutherland, in 

 1888, where he says it increased abundantly. It is doubtful 

 whether it has been found in Ireland. 



Its general distribution is England, North France, 

 Holland, Belgium and North Germany. It is quite unknown 

 however on the western coast of England, but its range 

 in that country is exceedingly compact, and embraces every 

 county on the eastern and southern coasts, from south 

 Northumberland to south Devon, together with the neigh- 

 bouring inland counties, without a single detached outlier 

 throughout its whole range. 



During the present summer (1920) specimens were col- 

 lected by me at Charlestown on the Forth, on an old ballast 

 heap that has not been in use for many years, at a spot on 

 the heap almost composed of limestone. For several years I 

 had collected during the winter months some small Helixes 

 hibernating below the limestone blocks, which puzzled me 

 very much ; but at last I put them down as Helix riifesceiis 

 {striolata of Taylor's book). This month (July) I took a friend 

 who was interested in shells to see them, but could not find one. 

 On the vegetation all round the place, Helix cantiana was in 

 abundance, and on less than a square yard I collected over 

 two dozen. No doubt this mollusc has been introduced with 

 the ballast coming into Charlestown harbour many years 

 ago, and it has now taken a firm hold. Helix virgata also 

 occurs on these ballast heaps, whence it was recorded by 

 Mr William Evans in 1904. Specimens have been submitted 

 to Mr J. \\\ Taylor, who confirms the identifications. 



105 AND 106 T 



