SYSTEMATICALLY ARRANGED BY DR. T. T. KAUP. 
parte, Prince of Canino, Messrs. Bruch, John and George Gray, 
Gene, Gould, Horaeyer, Horsfield, Jager, Mitchell, Count You der 
Miihle, Riippcll, and his Royal Highness the Prince of Wurtemberg, 
who have so liberally seconded my endeavours, either by written 
communications, or by furnishing me with valuable materials. To 
Hr. Rlippell I owe the means of laying the first foundation of my 
labours, as he allowed me the fullest use of all the materials in 
the Senkenberg Museum, and furnished me with nearly all the 
literature required. Once more, I offer my sincerest thanks to 
this noble-minded gentleman. 
The greatest personal gratitude, however, I think due to my 
honoured friend, Mr. George Gray, who, sacrificing his very scanty 
leisure time, gave me all the aid in his power, and essentially facili- 
tated my researches in the British Museum. We had silently 
agreed to correct our respective opinions, and to admit none 
without the severest criticism. What in the Synonymy belongs 
either to Mr. G. Gray or to myself, will appear by Mr. G. Gray’s 
List of the Specimens of Birds in the British Museum, Part I., 
Accipitres, which, with all its little imperfections as a first essay 
of so gigantic a labour, has served me as a most solid guide. 
Therefore, once more, I repeat my warmest thanks to him who- 
has favoured me, besides, with so many marks of friendship, the 
recollection of which will ever be dear to me, as it must be to all 
who know him. 
Probably few readers of this Monograph will be acquainted with 
my classification of mammalia and birds ; and I expect, therefore, 
to be asked by them, “ Why are the Accipitres, and the families’, 
subfamilies, the genera and subgenera of them arranged thus, and 
not in another way?” For this reason, I think it a duty to my 
readers, to explain the principles of my arrangement, of which a 
well laid foundation appears to be of vital importance to the whole 
system However, before entering upon the subject, I must ob- 
serve, that I presuppose a considerable knowledge of forms, because 
I am often obliged to anticipate, and to my regret, I cannot give 
drawings of all the genera. I also must beg my readers to set 
themselves free from their prepossessions in favour of any systems 
in order to be able to follow impartially my investigations. The 
iappy few who have large collections at their disposal, I would 
advise to study the actual forms which I adduce, in order to test „,v 
90-9 ^ 
