SYSTEMATICALLY ARRANGED BY DR. T. T. KAUP. 
Falconince, represents the Milvine type, as expressed in Ictinia. 
These are the reasons why Tinnunculus vespertinus (particularly 
the male) are so like Ictinia in the construction of the wings and 
the colouring of the plumage. 
I attribute the first rank to the Spiziaetus in the third sub- 
family, Accipitrince : because in this genus we observe the vaulted 
bill, beginning from the cere ; and because we see in their feathered 
feet, and in their toes, covered with fine dissected scales, an ap- 
proximation towards the mammalia ; besides all this, they are the 
noblest creatures in their whole subfamily. 
For the same reasons does Aquila take the first rank as a 
genus among the fourth subfamily, Aquilince. A bill curved from 
the cere, however, exists only in their first subgenus, Hieraetvs 
(Aq. pennata et morphnoides ), they are the noblest forms in their 
whole subfamily. Among the last subfamily of the Buteonince , 
Buteo takes the first place; because the first subgenus, Archibuteo , 
with their feathered tarsi, are obviously the noblest of their genus 
and whole subfamily. Among the Gallince (fifth order) the family 
of Cracidce take the first rank, on account of their vaulted and 
curved bill ; their graceful attitude and sagacity, also at once indi- 
cate their rank. 
We have assigned to the Psittacidce as a family— and in this, 
as the highest member to the Zygodactyly— the first rank as an 
order. Among the Ornithes (Passer es), we have given to the 
Fringillidce, and by them to the Conirostres as suborder, the first 
rank. We showed it to be reasonable, that the Pressirostres among 
the Grallatores, the Accipitres among the Ichthy ornitlies, and the 
Cracidce among the Gallince should occupy the first rank ; we 
may now proceed to characterize the class of birds, and we put 
the question : W hat is it which makes a bird to be a bird ? After 
having found out the true bird type, and abstracted from this the 
characteristics, it will now be an easy task to give to all the sub 
orders and families which represent the true bird in their order 
suborder, &c., their respective second rank, which is the very same 
second rank which the class of birds itself represents in the first 
subkingdom of real animals. 
In the second class of birds, the system of respiration, from 
Mhicli the organs of circulation cannot be separated, is particularly 
perfect. In this class there exists, without any exception,' iln 
