PREFACE. 
IX 
works 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 laborious 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 the terms and 
fundamental principles ; and in the veget- 
able and mineral departments, very many 
excellent helps are offered to the young and 
inexperienced student : but there is not 
one* of this description, which is calculated 
to throw any light upon the difficulties of 
* Since the first edition of this work was published, 
two other Introductions to the Science of Conchology 
have appeared ; both of which are mentioned in the 
List of Authors. 
