VI PREFACE. 



A few words of explanation are necessary with ref 

 erence to the joint authorship of the book. The draw 

 ings and the investigations, where they are not referred 

 to other observers, have been made by MR. A. AGASSIZ, 

 the illustrations having been taken, with very few ex 

 ceptions, from nature, in order to represent the animals, 

 as far as possible, in their natural attitudes ; and the 

 text has been written by MRS. L. AGASSIZ, with the 

 assistance of MR. AGASSIZ S notes and explanations. 



CAMBRIDGE, May, 18G5. 



