See page in:
1859
1860
1861
1866
1869
1872

Compare with:
1859
1861
1866
1869
1872

bats. 1859 1860 1861 1866 1869
bats, but is now believed to belong to the Insectivora. 1872

It has an 1859 1860 1861 1866 1869
An 1872

1 blocks not present in 1859 1860 1861 1866 1869; present in 1872
This flank-membrane is furnished with an extensor muscle.

I see 1860 1861 1866
I can see 1859
there is 1869 1872

had been formed by 1859 1860 1861 1866 1869
was developed in 1872

case of the 1859 1860 1861 1866 1869
OMIT 1872

convert it 1859 1860 1861 1866 1869
have converted the animal 1872

bats which have 1859 1860 1861 1866
certain bats which have 1869
certain bats in which 1872

see 1859 1860 1861 1866 1872
yet see actual 1869

rodents or new beasts of prey immigrate, or old ones become modified, and all analogy would lead us to believe that some at least of the squirrels would decrease in numbers or become exterminated, unless they also became modified and improved in structure in a corresponding manner. Therefore, I can see no difficulty, more especially under changing conditions of life, in the continued preservation of individuals with fuller and fuller flank-membranes, each modification being useful, each being propagated,
until,
until
by the accumulated effects of this process of natural selection, a perfect so-called flying squirrel was produced.
Now look at the Galeopithecus or
so-called flying
flying
lemur, which formerly was
falsely
falsely
ranked amongst bats. It has an extremely wide
flank-membrane
flank-membrane,
stretches
stretching
from the corners of the jaw to the tail, and
includes
including
the limbs
with
and
the elongated
fingers.
fingers:
the
the
flank-membrane
flank membrane
flank-membrane
is,
is,
also,
also,
furnished
furnished
with
with
an
an
extensor
extensor
muscle.
muscle.
Although no graduated links of
struc- ture,
structure,
fitted for gliding through the air, now connect the Galeopithecus with the other
Insectivora,
Lemuridæ,
yet I see no difficulty in supposing that such links formerly existed, and that each had been formed by the same
manner
steps
as
with
in
the case of the less perfectly gliding squirrels;
and that
and that
each grade of structure
had been
having been
was
useful to its possessor. Nor can I see any insuperable difficulty in further believing
it possible
it possible
that the
membrane connected
membrane-connected
fingers and
fore-arm
forearm
of the Galeopithecus might
have been
be
greatly lengthened by natural
selection.
selection;
and this, as far as the organs of flight are concerned, would convert it into a bat. In bats which have the wing-membrane
extends
extended
from the top of the shoulder to the
tail
tail,
and includes
including
the hind-legs, we perhaps see traces of an apparatus originally
fitted
constructed
for gliding through the air rather than for flight.