PREFACE. xiii 



species of Vertigo, kindly made by him expressly 

 for this work. Lithographic facsimiles of them will 

 be found on Plate X., and I trust that by their aid 

 the reader will be enabled, without much trouble, to 

 identify the several species of these minute but very 

 interesting molluscs. 



12, WESTBOURNE CRESCENT, HYDE PARK, W., 

 July 8, 1880. 



