xvi author's preface. 



merely giving accurate views, supported by the most 

 striking illustrations. In the present volume I am 

 forced to preserve this feature, unless I were to 

 produce a completely new work. 



Such as it is, I trust that this treatise may be 

 accessible to all who are accustomed to serious read- 

 ing. At the same time, it will present to naturalists 

 the principal facts with which they are acquainted, 

 arranged in a manner peculiarly my own, and with 

 references to several works scattered here and there. 

 Perhaps in these different aspects it may prove of 

 service. Such, at all events, is the object with 

 which I publish it. 



March 15th, 1862. 



