PREFACE. V 



in different languages, afford; — by this 

 means have been rendered attainable by all, 

 the hidden treasures of a most interesting 

 science, the valuable fruits of the labo- 

 rious investigation of a few. 



In each class of the animal kingdom, at 

 least in those which are most generally 

 studied, there is some work, in the English 

 language, explanatory of theterms, and fun- 

 damental principles; and in the vegetable 

 and mineral departments, very many excel- 

 lent helps are offered the young and in- 

 experienced student: butthereis notone^of 

 this description, which is calculated to throw 

 any light upon the difficulties of Concho- 

 logy. That some difficulties do exist in 

 this branch of study, will readily be allow- 

 ed ; but at the same time we cannot but 



