in the same manner as the study of geographical science is 

 facilitated by the naming of the indentations and prominences 

 of a line of coast, or that of meteorology by the graduation of 

 the instruments used, names will be used for the most promi- 

 nent and important of the variations. It will not follow from 

 the adoption of this course that undue importance will be 

 attributed to such differences, as the projectors are well aware 

 that varieties are not of themselves distinct and separate 

 entities, and look upon the naming of such forms as being as 

 purely a matter of convenience as is the sub-division of the scale 

 of a meteorological instrument. It is therefore hoped that 

 correspondents will assist by furnishing specimens and notes to 

 as large an extent as possible, so that by the examination of a 

 sufficiently large amount of material just and sound conclusions 

 may be arrived at. 



Geographical Distribution 



will also be one of the salient features of the work, and it is in- 

 tended to treat of it systematically, precisely and exhaustively 

 and from personal examination of specimens from as many 

 districts as possible. The accumulation of material for the 

 proposed detailed account of 



Distribution in the British Isles, 



is perhaps the most formidable part of the present undertaking, 

 from the difficulty of getting together specimens from a sufficient 

 number of districts. The projectors wish therefore to make it 

 clear that they wish to have specimens of all species and varieties, 

 even the very commonest (without any exception whatever) from 

 each of the 154 counties and vice-counties into which (by subdivi 

 sion of the larger counties) the British Isles are divided for this 

 purpose. It consequently follows that for obtaining the material 

 they are dependent upon conchologists (and indeed naturalists) 

 generally, throughout the country. Valuable specimens will of 

 course be carefully returned after being examined and the best 

 return possible will be made for assistance, even to the extent of 

 presenting copies of the work when published to some of the 

 most zealous and liberal of its supporters. 



