PREFACE TO THE THIRD EDITION. 



One of the large north galleries approached from the Bird Gallery 

 is devoted to the exhibition of the extensive Class of Mollusca. 

 Specimens of the types of all the principal divisions of this Class 

 are exhibited, either entire and preserved in spirit, or as models. 

 However, as not the animals, but their shells have always been a 

 favourite object of study, and a popular source of pleasure to 

 collectors, the exhibition of the species of shells has been made as 

 complete as the space of this Gallery admitted. It. has thus proved 

 adequate for the requirements of the majority of visitors and students 

 who consult this Collection. A separate series of British Shells is 

 exhibited in some small table-cases along the west wall. 



This Gallery also contains the exhibited series of Polyzoa, 

 Brachiopoda, and Tunicata. 



The Starfish Gallery, so called from one of the best-known types 

 of the Echinoderma, contains an exhibition of the animals of this 

 Class, as well as of the somewhat heterogeneous assemblage of 

 creatures which are comprised under the popular name of Worms 

 {Vermes). These animals possess greater attraction to students of 

 Natural History than to the general public, and many, from their 

 small size or the soft nature of their body, are not suitable for 

 exhibition. Therefore no attempt has been made to show more than 



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