JOURNAL OF CONCHOLOGY. 289 



Cowry is to be found in the National collection, or in the latest 

 monograph (that of Mr. S. Raymond Roberts in Tryon's Manual 

 of Conchology, vol. vii.,). 



With this shell I have the melancholy satisfaction of 

 associating the name of my late friend Jonathan Rashleigh, Esq., 

 Junr., of Menabilly, Cornwall, who died in December, 1872, at 

 the early age of twenty-seven. His collection of Cyprsea was 

 extremely large and perfect ; and had he lived, he would have 

 made great mark in a science to which he was profoundly 

 attached. The type of this species, at present unique, is in 

 my collection. 



ON THE VARIATION OF 

 BRITISH LAND AND FRESHWATER MOLLUSCA. 



By JOHN W. TAYLOR, F.L.S. 



Membre Honoraire de la Soci^t6 Malacologique de France. 



Being his Valedictory Address as President of the Conchological Society 

 FOR the Year 1887. 



I HAVE considered that a few of the observations bearing upon 

 variation, which I have collected for use in the Monograph of 

 our native species of Land and Freshwater MoUusca, upon 

 which myself and Mr. Roebuck have been engaged now for 

 some years, would perhaps be of some interest, and tend to give 

 direction and point to our observations as to the manner in 

 which natural selection or environment is modifying the various 

 species that come under our notice, and thus producing the 

 varieties, which under favourable circumstances may ultimately 

 develop into new and distinct forms. 



Without an intimate knowledge of the great variability of 

 species, I submit that no one can hope successfully to correlate 

 our recent with our fossil mollusca, and if this be acknowledged 

 it shows clearly the immense importance of the study of varia- 



