iSgi.] 



THE BRITISH NATURALIST. 



59 



Mab.,) Bedford Park ; ylgiio-limaxagreslis, var. sylvaticiis, Moq., Acton. — H. W. Barker, 

 Hon. Sec, 



LANCASHIRE AND CHESHIRE ENTOMOLOGICAL SOCIETY. 



The Monthly Meeting was held on Monday, February gth, the President — Mr. S. 

 J. Capper, F.L.S., F.E.S. — in the chair. Mr. Brockton Timlin, of Chester, was pro- 

 posed for membership. Mr. VV. E. Sharp read a paper on " Variation and heredity : 

 some recent speculations on their origin." The author explained the various hy- 

 pothesis put forward by such men as Wallace, Darwin, and Le Mark, on the phe- 

 nomena of variation, showing the points of difference in the theories of each, and 

 fully discussing the subject of pangenesis as relating to hereditary variation. The 

 President exhibited some fine varieties of Bomhyx rubi ; Mr. Gregson — a beautiful 

 variety of Sciaphila colquJioiinana, bred from larva collected at Scarlet Rocks, Isle of 

 Man, in i88g ; Mr. R. Newstead — a specimen of the rare Vanessa antiopa, captured in 

 Cheshire, 1872; Mr. Stott — varieties of British Lepidoptera ; the Rev. H. H. 

 Higgins — a drawer of African butterflies ; and by Mr. Wilding — a series of Silpha 

 atrata,vaT. subrotundata, from Ireland. — F. N. Pierce, Hon. Sec,, 143 Smithdown Lane, 

 Liverpool, 14th February, 1891. 



Mollusca. 



BIBLIOGRAPHY. 



C. A. Westerlund. Faun. Pal. Binn. (continued from p. 21). 



Many of the European fresh -water genera are so exceedingly poly- 

 morphic that there is, apparently, no end to the number of forms, 

 called varieties or species, according to the views of the authors who 

 write about them. While it cannot be denied that full information 

 about all these is very desirable, it seems quite unnecessary to call 

 them all species, after the manner of the Bourguignat school. Very 

 much remains to be ascertained as to the permanence or otherwise of 

 the various characters on which these so-called species are founded ; 

 but from what we know of the variability of fluviatile mollusca under 

 different conditions, there is reason to believe that a very large pro- 

 portion of the species of LimncEa, Unio, &c., described of late years, 

 would not prove permanent if removed to new environment — that is 

 to say, the supposed specific characters would not tend to be inherited. 

 Of course, it will be argued that under circumstances of isolation and 

 new environment, all species tend to change ; but surely characters 

 which are produced by circumstances during the lifetime of the indi- 

 vidual can hardly be considered specific, unless evidence can be found 

 to show that they are transmitted to the offspring. We should prefer 



