BIRDS OP PREY. THE TYPICAL FALCONS. 297 
descriptions in books ; and others, from not being in 
our own possession, cannot be re-examined, or laid 
upon our study table, while this inquiry is going on. 
We have found, in short, that notes taken in public 
museums, rarely, if ever, completely answer the ultimate 
purpose for which they are intended. Something of 
importance, not known to be such at the time, is gene- 
rally overlooked ; while other details, tlirni thought of 
importance, sometimes turn out of very secondary con- 
sequence. Several reasons induce us to make these 
observations on the present occasion. In the first place, 
the reader will be informed what facts repose upon pCT- 
sonal observation, and what are taken upon trust. He 
will further see the importance of collecting, as far ^ 
possible, under his own eye, the subjects upon which he 
intends to write ; and he will learn to appreciate the 
value of those very few descriptive works which mi- 
nutely describe the structure of every species, and aU 
its deviations from its acknowledged type. 
(244.) Commencing with the genus Fako, as the 
most typical of the whole family, we observe in them 
the highest development of that structure which is best 
adapted for rapine. Their wings, although not so long 
as in some of the kites and buzzards, are yet more 
pointed, the second and third quill being the longest ; 
and although the character is applicable only to the 
typical species, it never is so far lost but that the stu- 
dent can at once discriminate a falcon from a hawk. 
The most prevalent distinction, however, of the group 
lies in the bill, which is always short, and the tooth 
near the tip invariably angulated. Ihe subgenus 
Falco, to which we are now more especially alluding, 
has only a single tooth in the upper mandible, behmt 
which there is an incipient festoon or sinuated pro- 
jection, analogous to that which is so much 
veloped in the next generic group *)• These 
birds present among themselves some very slight vari- 
ations, not, however, of any material consequence. In 
some, as in the small rufous-backed species, allied to 
