AUTHOK'S PREFACE. 



IN the preparation of this Treatise, the Author has kept steadily in 

 view the objects at which he has aimed in the preceding volumes, and 

 in the attainment of which he trusts that he has been in some degree 

 successful ; namely, the Exposition of the principles of Science in their 

 simplest form, and the Illustration of these by the most useful and in- 

 teresting examples. He has so fully explained his views on the utility 

 of the study of Zoology, and on the mode in which it may be most 

 advantageously pursued, in the Introduction and First Chapter of the 

 present volume, that he considers any further remarks on these sub- 

 jects here uncalled for. 



The general account of the Classes is translated, with some additions 

 and modifications, from the " Cours Elementaire de Zoologie " of M. 

 Milne-Edwards ; a work adopted by the French Government as the 

 Text-Book of instruction, in the Colleges connected with the Uni- 

 versity of Paris ; and the whole of the beautiful illustrations prepared 

 for that Treatise will be found in the present volumes. For the more 

 detailed accounts of the Orders, Families, &c., as well as for the first 

 Two Chapters, the Author is solely responsible. In the preparation of 

 these portions of the work he has availed himself of the best and most 

 recent sources of information; and has endeavoured to adopt the 

 most approved systems of Classification. As scarcely any two Na- 

 turalists agree, however, on this head, the choice has been frequently 

 a matter of difficulty ; and he cannot suppose that he has been always 

 equally successful. He has adopted as his chief guides, the last 

 Edition of the Synopsis of the British Museum ; and the Pictorial 

 Museum of Natural History, at present in course of publication ; and 

 to the latter of these works he is also under great obligation, for 

 numerous details, obtained from sources to which he might not other- 

 wise have gained access. 



A little reflection will show, that any general Zoological Treatise 

 must necessarily be in great part a Compilation from the works of 

 other Naturalists ; and the merit of an Elementary work like the pre- 

 sent, must consist rather in the judgment shown in the selection and 

 arrangement of the materials, than in the originality of its contents. 

 How far the Author has succeeded in his present attempt, it will be 

 for his readers to decide. 



W. B. C. 



