‘98 TRANSACTIONS OF THE | JAN. 9, 
emargination of the vane. ‘To give the portion of the vane thus 
cut away sufficient strength and breadth to add its share to the 
sustaining power of the wing, the vane would have to be thickened 
to make it more rigid, and broadened to fill the wide inter- 
val between the tips of the feathers, thus making a heavy club- 
shaped clumsy tip to the feather, and obviously decreasing the 
efficiency of the wing as an organ of flight. 
Further evidence of the pertinency of this explanation of 
emargination is afforded, when we recall the fact that emargina- 
tion is confined to a certain type of wing, and that when absent 
the wing is of an entirely different type as regards its general 
form. The wing of the frigate-bird well illustrates the form 
of wing in which there is no such emargination. It isa very 
long, acutely pointed wing, in which the first primary is the 
longest, the second, third, and all of the following being succes- 
sively shorter, and all sharply pointed, so that when the wing is 
fully extended there is practically no open space between the 
tips of any of the primaries. 
There are three principal types of wing in relation to its form: 
I. A very long, pointed wing, in which the first primary is 
the longest, and all the outer primaries are narrowed toward the 
tip, and successively decrease rapidly in length, rendering no 
emargination necessary. Examples: man-of-war bird, alba- 
trosses, shearwaters, gulls, terns, plovers, sandpipers, swallows, 
swifts, etc. 
II. A short, rounded wing, in which the tip is formed by the 
four or five. outer primaries, which are sub-equal in length. 
Here, owing to the shortness of the wing, the tips of the pri- 
maries are not separated when the wing is fully extended. 
Here no emargination is necessary, and noneexists. Hxamples: 
sparrows, and the smaller song-birds in general ; also rails, 
quails, tinamous and many grouse. 
III. A long, pointed wing, but in which the tip is formed not 
by either the first or second primaries, but by the third, fourth, 
and fifth, and in which the six or seven outer primaries form 
the point of the wing, and are graduated in length from the 
longest, which is about the fourth or fifth, outwardly to the 
first, and inwardly to about the seventh or eighth. This form 
of wing is typically exemplified in hawks, eagles, buzzards, 
vultures, ravens, crows, etc. 
Between these types of wing there is every stage of intergra- 
dation, with corresponding variation in the emargination of the 
primaries, in the form of wing characterized by this structure. 
The true falcons have a very pointed wing, in which the longest 
primary is the second ; the first is somewhat shorter, and is the 
