THE 



BRITISH NATURALIST. 



NEW SERIES* 



THE BAND-VARIATION OF HELIX NEM ORALIS AND H. 

 HOE TENS IS IN THE BRITISH ISLES. 



BY T. D. A. COCKERELL, F.Z.S. 



For some years past I have been collecting the records of the varia- 

 tion in the banding of these two species ; and as no list of the "band- 

 formulae " observed in the British Isles has appeared, it may be of 

 service to publish the following, which is, I think, almost or quite com- 

 plete up to the time I left England, The records are scattered over the 

 pages of several magazines, but it seems scarcely worth while to give 

 full bibliographical references. I have accordingly been content to 

 quote after each formula the name of the author who first published it, 

 whether in England or abroad. A few marked " f. nov." appear not 

 yet to have been published. The number of variations might be largely 

 increased by taking into account the differences of colour, but I have not 

 found much correspondence between colour and banding, except that 

 shells of certain colours {e.g. lilac H. hortensis) are usually bandless. 

 The banding differs greatly according to locality, and considerable 

 difference is often to be observed in this respect between British and 

 Continental examples. It is also to be noted that although H. nemoralis 

 and H. hortensis are very closely allied, they differ much in their band- 

 variation, and the former is decidedly more variable than the latter. 



The " band-formula " method is very generally known, but it may be 



