A CHECK-LIST OF THE SLUGS. 



By T. D. a. COCKERELL, F.Z.S., F.E.S., 



Professor of EntoDioioi^y and Zoology, Neiv Mexico Agricttltiiral College. 



WITH AITENDIX AM) NOTES 



By WALTER E. COLLINGE, 



Demonstrator of Biology, Mason College, Birmingham. 



The present list is intended to include all the names, generic, 

 specific, or varietal, which have been proposed for slugs. The writer 

 is responsible for the arrangement, which is in accordance with his 

 present views, but it is not supposed for a moment that it is in any 

 degree final, and there can be no doubt that the labour of students 

 in the near future will show many changes to be necessary. In 

 many instances it is impossible to make sure of the correct location 

 of a slug without such study of specimens and bibliographical 

 research as are quite beyond the power of the compiler, situated as 

 he is away from museums and malacological libraries. Those who 

 have the opportunity may do good service by critically examining 

 the doubtful names in this list, and determining their true value. 



When the validity of a species or variety is doubtful, it is best in 

 a check-list to give it the benefit of the doubt. Too great readiness 

 to reduce names to synonymy may lead to blunders which are after- 

 wards the source of much misunderstanding. For example, on 

 reading Mabille's numerous descriptions, one is impressed by the 

 fact that the author did not distinguish between specific and varietal 

 characters, and the natural tendency is to assume that none of the 

 so-called species are valid. Yet subsequent research has shown 

 that some of them are perfectly distinct. Again, when false 

 synonymy has been proposed, it is often followed by author after 

 author, when a glance at the original description by any competent 



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