SYSTEMATICALLY ARRANGED BY DR. T. T. KAUP. 
respective sub-orders, analogous forms, whereas the Hirundince, 
Cypselmce, Podargince , Caprimulgince, show real affinities. The 
analogous forms may be separated by sub-orders, which never can 
take place with affinities of form. 
If these gentlemen would give up their false application of ana- 
logies, and make their anatomical knowledge serviceable for the 
discovery of the characteristics of a single genus, and be guided 
by their pure sense of nature, how speedily and gloriously would 
our science improve. 
To bring the coverings of the tarsus and the number of the quill- 
feathers into accordance with the existence or the want of the 
apparatus of the singing muscles, as Cabanis has done,* I own is 
meritorious ; but to use these peculiarities as characteristics of 
order and sub-order, is, according to my judgment and knowledge, 
altogether wrong. The feathered tarsus is a characteristic of a 
true bird, and a vestige of it appears in Nisus , to which I have 
assigned the second rank of the third subfamily, Accipitrince, like 
the rank of the class birds. This genus, however, occupies by- 
no means the highest rank ; and besides, no ornithologist will 
place the Falconince , which have no indication of this charac- 
ter, as members of the first subfamily, and Nisus as the second 
genus of the third subfamily, Accipitrince. The capricious sugges- 
tion, that the feathered tarsus is to indicate the highest order of 
birds (it only constitutes a true bird), will generally not succeed, 
since a tarsus covered with very small scales or feathers, stands 
nearer to the naked or hair-covered foot of mammalia, than a 
tarsus covered with scuta, or small scales, which is surely more 
analogous to the covering of the feet of reptiles. In spite of 
that, however, neither the Strip idee, where the tarsi and toes are 
mostly feathered, can be placed above the Falconidce, nor Elanus, 
with its finely grained scaly tarsi, above the Falconidce; it is 
only a partial character, analogous to the mammalia, while other 
decisive marks are wanting. 
I must openly avow, that I have not been so fortunate as to find 
altogether, decisive characters by which to designate in a few words 
the subfamilies of the Falconidce, ; yet, nevertheless, I am firmly 
convinced, that the genera are rightly arranged. I might have 
* Wiegrn. Arch. 1847, p. 186 . 
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