244 



SCALARIFORM HELIX NEMORALIS. 



By R. welch. 



(Read before the Society, May 14th, 1902). 



Plate II. 



While collecting information some years ago about the large number 

 of sinistral forms of this species that are regularly found near Bun- 

 doran, Co. Donegal/ I found that a fair number of very high-spired 

 and really good scalariform specimens also appeared at the rate of 

 three or four per annum. These, like the reversed examples, are 

 picked out of the many thousands of the ordinary form that are col- 

 lected for necklace making in the hollows of the Finner Dunes by old 

 peasant women. These necklaces, like those at Southport and Black- 

 pool, are sold to summer visitors, but the "sports" are reserved for 

 various special "markets" and are passed on regularly to a favoured 

 few. The old women sometimes call them "spiders," "spidery" being 

 sometimes used in the north of Ireland for anything slender or tall. 



I have now obtained records of about forty shells that were truly 

 scalariform, and a rather larger number that were very high in the 

 spire ; they vary very much both in size and shape, some having a 

 much deeper suture than others, but these are not necessarily the 

 highest specimens (PL II., fig. 20). 



For instance, a fine rich olive-coloured shell, from Mr. Brockton 

 Tomlin's collection, is not a high-spired form, yet it has the deepest 

 suture and roundest whorls of any I have seen. In the plate I have 

 arranged a graduated series, from fig. i, a mere high-spired form, to 

 fig. 16, a fine shell, 34 mm. high, also from Mr. Tomlin's collection. 

 This is the finest "sport" of this species that has come under my 

 notice. A few years ago I had not seen any of these perfectly fresh 

 with epidermis intact, but during the last two years friends have 

 obtained several, Mr. W. A. Green, of Belfast, having been fortunate 

 enough to collect one alive not far from the Fairy Bridges, and there 

 are several in the Tomlin collection from which the majority shown 

 on my plate were selected, the remainder being from Mr. W. 

 Swanston's or my own. The specimens figs. 17-19 on the plate seem 

 to have been normal up to the time the animals received some injury, 

 after which they finished the shell in a more or less scalariform shape. 

 Fig. 19 is an especially curious shell, the final whorl having turned 

 down sharply almost at right angles to the rest, forming a rough, rather 

 angular mouth. The banding is as varied as in the normal form, and 

 some have the very fine or dotted band loooo or 02000 so character- 

 istic of many Bundoran specimens. 



I h-ish Naturalist, voL g, p. 163, igoo. 



