74 AN EARLY NEOLITHIC KITCHEN-MIDDEN. 



The list is perhaps more striking from the absence of so many of 

 our commonest living species than for anything else ; but there are 

 two which call for special attention. Helix nemoralis and Helix 

 hortensis are represented each by an extreme form at Blashenwell, 

 and these occur by the hundred without any intermediate forms. 

 The distinction of the two is so marked that no naturalist seeing a 

 large series from Blashenwell, and unacquainted with the 

 variability of the living snails, would for a moment hesitate to say 

 that they were good and well-marked species, belonging merely to 

 the same section of the genus. The following descriptions will 

 show this : 



Helix nemoralis (from Blashenwell). 

 Shell large, depressedly globular, amber coloured or 

 yellow, without bands, lip dark. 



Helix hortensis (from Blashenwell). 



Shell smaller and more globular than H. nemoralis, 

 whitish, bands five, two narrow above and three 

 broader below, often widened till they become con- 

 fluent, lip white. 



The difference is not due to deficiency of colour, for the dark- 

 lipped H. nemoralis is always amber-coloured or yellow, but entirely 

 without bands, while the smaller white-lipped H. hortensis is 

 whitish or grey and five-banded, a single specimen only having one 

 of the narrow bands missing. The banded H. nemoralis^ so common 

 at the present day, is wanting at Blashenwell, as are all intermedi- 

 ates or hybrids between the two forms. The exact meaning of 

 this exceptionally strong contrast between the Helix nemoralis and 

 H. hortensis found mingled at Blashenwell is not clear, and as yet 

 I have been unable to examine a sufficiently large series of these 

 species from Palaeolithic or earlier deposits to throw any light 

 on the question. 



When an enquiry of this sort is undertaken, it is certain to lead 

 one into all sorts of by-paths and to produce results quite other 

 than those expected. The examination of the Blashenwell tufa 



