1 02 INTRODUCTION. 



thologist that the classification here employed will 

 be in conformity with that theory, on the principles 

 of the natural system, which we have already given 

 to the world in other works*. The species will 

 be arranged under their natural families ; and when 

 they possess any remarkable relations, not hitherto 

 observed, occasional notices on these points will be 

 introduced. Commencing with the Raptorial order, 



or the 



BIRDS OF PREY, 



we find several species mentioned by different 

 authors as inhabiting Senegal, which we are com- 

 pelled to omit ; partly because we cannot vouch for 

 their locality, not having seen imported specimens ; 

 but more especially because we studiously avoid, on 

 nearly all occasions, copying from others the de- 

 scriptions of animals we have never seen, a custom 

 which has led, in a great number of instances, to 

 erroneous accounts, drawn up at a time when the 

 science was emerging from its infancy t. Our work 

 may thus be thought to loose something in the 

 variety of its materials, but this we trust will be 

 compensated by its greater originality and accuracy. 

 Besides, we desire to make our volume not only 



* Fauna Boreali Americana, or Northern Zoology ; Clas- 

 sification of Animals, &c. 



f Even some of the best ornithologists pay so little atten- 

 tion to the variations of structure, and pass over so many 

 points necessary to be understood, that their descriptions are 

 of little service beyond informing us on the mere colours of 

 the plumage. Those for instance, in the Planches Coloriees of 

 MM. Temminck and Langier, are particularly defective in this 

 respect 



