84 ON THE CliASSIPICATION OP BIRDS. 
into two series : on one side it gradually diminishesj 
through the raptores and the imessores ; and, on the 
other, through the gmUntores, until both these meet in 
the order rusores, where the flight is reduced to its 
minimum. We shall now describe such modifications 
of the wing as influence these different degrees of 
motion ; considering these members as, 1. acuminated; 
2. falcate ; 3. pointed, 4. rounded, 5. ample, 6. abbre- 
viated or obsolete. In regard to their comparative extent, 
a wing, however it may he otherwise constructed, is 
termed long, when it extends beyond the middle of the 
tail ; moderate when it reaches nearly, or to, that member ; 
and .short when it just extends to the base, and the pri- 
mary quills are not much longer than the secondaries. 
(78.) 1. Acu.minated wings are those adapted for the 
most rapid and long-continued flight. The most per- 
fect examples of this form are seen in the oceanic 
genera ; and the frigate pelicans may be instanced as 
the most powerful flyers in the creation. But as few of 
our readers are likely to see these birds, tve may instance 
the swallow as exhibiting a perfect example of an acu- 
minated wing (Jig. 41.). The first quiU is generally the 
longest, although it sometimes happens that there is 
scarcely a perceptible difference between tliat and the 
second : the rest, however, gradually, but regularly, 
diminish at almost equal intervals, until they reach the 
lesser quills, which are little more than one third tlie 
length of the exterior primaries, the whole of which are 
very broad, hut gradually taper at their extremities. 
The lesser quills, on the contrary, are not only un- 
usually short, but 'terminate so abruptly that they ap- 
pear to have their ends cut off at that part ; however, 
