55^ 



LIST OF BRITISH NON-MARlNE] MOLLUSCA. 



By B. B. woodward, F.L.S., F.G.S., etc. 



(Read before the Society, January 14, 1903). 



In drawing up the accompanying list of British Non-Marine MoUusca, 

 in accordance with the latest views of nomenclature, regard has been 

 had in the first place to the " law of priority" where applicable. In 

 such cases, however, where it is known that an earlier authority has 

 mixed up two or more species under one specific name and no subse- 

 quent investigator has definitely selected one form and removed the 

 others, but different authors have disputed over and muddled the nomen- 

 clature, the course pursued has been to select those earliest names 

 concerning which there is no dispute, the object of nomenclature 

 being to have a series of names for forms that will enable various 

 workers to know exactly what form is meant by a given name. 



This course is specially applicable to certain disputed forms in the 

 Linnean collection. It must be borne in mind that the specimens in 

 this celebrated collection were kept in open receptacles on which the 

 name was written, while on some few examples the number of the 

 species in the tenth edition of the "Systema" is written in ink. That 

 in the hurried transferrence to this country, it was very easy for mis- 

 placements to occur, while Sir J. E. Smith is known to have added to 

 it, and to have replaced specimens by what he considered finer ex- 

 amples ; nor did its present custodians always exercise such wise care 

 of it as they now take. So that the occurrence of a given form in a 

 certain tray in that collection by no means implies that it is the rightful 

 occupant. 



As regards varietal names, those merely indicative of variations in 

 colour, size, etc., are discarded (with few exceptions), the only names 

 left being those of forms which, owing to anatomical differences or 

 geographical distribution, have been or might be by some ranked as 

 distinct species. 



With respect to the general classification, it has appeared better for the 

 present to adopt a modification of Fischer^ than to follow the tentative 

 grouping put forward by Pilsbry,^ which last seems to require further 

 investigation, full details not having as yet been published by him. 



The slugs generally I have not personally investigated in detail, but 

 the nomenclature here proposed seems the best from an arm-chair 

 point of view. Mr. CoUinge informs me he has a work in the press 

 and shortly to be issued, which will give full details on the subject as 

 known to him. 



1 Manuel de Conchyliologie. 



2 Proc. Acad. Nat. Sci. Philadelphia, J900, pp. 563-4. 



