SYSTEMATICALLY ARRANGED BY DR. T. T. KAUP. 
though the authors of such systems might anticipate that their 
arrangements harbour death in the core, and will enjoy but a short 
lived existence. 
One of the principal mistakes in ornithology, as I already ob- 
served, is, that subgenera are considered as real genera, and that 
on their first appearance they are not arranged under their true 
genera. The consequence of this mistake is, that the subgenera 
which belong to but one large genus, are torn asunder, and put into 
a variety of subfamilies, according to wrongly conceived analogies. 
Thus the subgenera occasion the greatest confusion, and thus 
are particularly apt to puzzle the student of ornithology, who 
enters into science with a true sense of nature. If, however, the 
subgenera are arranged at once under their respective true genera, 
then they are an advantage to science, for they facilitate the survey, 
and make it possible to give short and precise distinctive characters 
to the species. Thus the mistake is avoided of marking the species 
of one part of the globe with the characteristics of subgenera, as 
has been done by Count Kaiserling and Blasius in their works, 
which in other respects possess much merit. How far I have done 
well to dissect genera like Circus and Nisus , &c., into their minutely 
varied subgenera, I must leave to he decided. I was partly obliged 
to do so, because other genera, as, Circaetus, Pernis, Elanus, 
Haliaetus, Pandion, Ibicter , &c., are divided into subgenera 
already known, whose characteristics are more obvious, though 
they are of no more consequence than those of the subgenera of 
Circus and Nisus. The characters indicated by me are, however, 
by no means difficult or minute, and may be easily recognised. 
If I made Circus cinerascens and pallidus into a subgenus, I 
did it not only on account of the short secondaries ( arm wings), 
the long primaries (hand icings), and the small number of emargi- 
nated quills ; but because, according to my principles, the Naucle- 
rus or swallow type is expressed by wings thus constituted. That 
both species get only in their third year the plumage of the old 
ones, and that the plumage of the middle age is so different from 
both, I consider as yet but as a secondary character, which, how- 
ever, may contribute to make us consider this little group’ to be 
perfectly characterized. 
By similar characters, as essential, the other subgenera are re- 
spectively distinguished. But by writing always Circus cineras- 
