70 The hish Naturalist. March, 



VARIATION IN MOUAJSCA. 



A Committee, consisting of Messrs. J. R. B. Masefield, F. 

 Taylor, R. J. Welch, and A. E. Boycott, has been appointed 

 by the Council of the Conchological Society of Great Britain 

 and Ireland for the purpose of conducting a collective in- 

 vestigation of phenomena connected with the variation and 

 life-history of British Land and Freshwater Mollusca. The 

 object of the investigation is to enquire into points liable to 

 general uncertainty, and to local or other variation, and into 

 the diffusion and dispersal of species, by collecting the results 

 of the individual experience of many naturalists. A certain 

 small number of subjects for investigation will be published 

 each year, and it is hoped that an abundance of replies will 

 be received , so that the results m ay be thoroughly representative. 

 The following five subjects have been selected for 1901 : — 



(1.) How far is the smell of "garlic" constantly associated 

 with Hyalinia alliaria ? Under what circumstances, and at 

 what seasons of the year, is it most noticeable 1 Does H. 

 alliaria seem to escape destruction by other organisms more 

 than the rest of the genus % Ts the smell of " garlic" found in 

 other species, and under what circumstances ? 



(2.) Have you in any case found any species or variety of 

 land snail constantly associated with any particular plant ? 



(3.) Is any preference shown by (1) H. aspersa, (2) H. 

 rufescens, for the neighbourhood of human habitations and 

 buildings ? If so, what explanation do }'ou consider probable ? 



(4.) What localities produce the largest specimens of 

 Anodonta ? Describe the nature of the water, soil, geological 

 formation, &c, and give dimensions, if possible, weight. 



(5.) In the genus Helix, where not indigenous, when and 

 how were any of the species introduced ? It is desired to put 

 on record, as far as possible, the date of introduction of any 

 species into any given locality, both from abroad into the 

 British Isles and from one part of the country to another. 



The locality for which each answer is recorded should be 

 carefully given, with any details of geological formation, 

 altitude, vegetation, &c, &c, which may suem desirable. All 

 returns should reach the Secretary (A. E. Boycott, The 

 Grange, Hereford), by September 1st, 1901. 



