while it may not appear exactly logical, still there
is something about it which seems to do the work,
and for that reason it is largely adopted.

WHY THE BIRD'S WING HAS A PRONOUNCED
BULGE.--Let us examine this claim. The bone
which supports the entire wing surface, called the
(pectoral), has a heavy duty to perform. It is so
constructed that it must withstand an extraordinary
torsional strain, being located at the forward
portion of the wing surface. Torsion has
reference to a twisting motion.

In some cases, as in the bat, this primary bone
has an attachment to the rear of the main joint,
where the rear margin of the wing is attached to
the leg of the animal, thus giving it a support
and the main bone is, therefore, relieved of this
torsional stress.

THE BAT'S WING.--An examination of the bat's
wing shows that the pectoral bone is very small
and thin, thus proving that when the entire wing
support is thrown upon the primary bone it must
be large enough to enable it to carry out its functions.
It is certainly not so made because it is a
necessary shape which best adapts it for flying.

If such were the case then nature erred in the
case of the bat, and it made a mistake in the