PREFACE. 



One of the large galleries to the north of the Bird Gallery is 

 devoted to the exhibition of the Mollusca. This extensive 

 group includes nearly 60,000 living species ; most of these are 

 represented in the Museum Collection, which consists of over 

 600,000 specimens. Models or spirit specimens of examples of 

 all the principal divisions are exhibited, and the models of an 

 Octopus and of the Giant Squid are the most conspicuous objects 

 in the Gallery. The shells of molluscs are a favourite object of 

 study and a source of pleasure to collectors, and the exhibition 

 of shells has been made as complete as possible, so as to be 

 adequate for the requirements of the majority of students and 

 visitors. The shells are arranged in systematic order in the series 

 of table-cases ; in addition a separate series of British Shells is 

 displayed in some table-cases near the west wall, and an instruc- 

 tive exhibit, prepared by Mr. B. B. Woodward, illustrating the 

 modifications of structure, form, sculpture, &c, in the shells of 

 Mollusca is placed in wall-cases on the same side of the Gallery. 



This Guide-book has been prepared by Mr. G. C. Robson, M.A. 

 It is to a large extent based on the late Mr. E. A. Smith's contri- 

 bution to the old Guide to the Shell and Starfish Galleries, but it 

 has been rewritten and much new 'matter has been introduced. 



Thanks are due to Messrs. A. & C. Black, Messrs. Macmillan 

 & Co., and Crosby Lockwood & Son, for kindly allowing the 

 use of cliches from illustrations in various works published 

 by them. 



C. TATE REGAN, 



British Museum (Natural History), Keeper of Zoology. 



London, S.W. 7. 

 March 1923. 



A 2 



