| → If a different case had been taken, and it had been asked how an insectivorous quadruped could possibly have been converted into a flying bat, the question would have been far more difficult, and I could have given no answer. 1859 1860 1861 |
| If a different case had been taken, and it had been asked how an insectivorous quadruped could possibly have been converted into a flying bat, the question would have been far more difficult to answer. 1866 1869 |
| During the summer this animal dives for and preys on fish, but during the long winter it leaves the frozen waters, and preys, like other pole-cats, on mice and land animals. 1872 |
|
| → Yet 1859 1860 1861 1866 1869 |
| If a different case had been taken, and it had been asked how an insectivorous quadruped could possibly have been converted into a flying bat, the question would have been far more difficult to answer. Yet 1872 |
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| → of the same genus; 1859 1860 1861 1866 1869 |
| OMIT 1872 |
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|
→If a different case had been taken, and it had been asked how an insectivorous quadruped could possibly have been converted into a flying bat, the question would have been far more difficult, and I could have given no answer.
→Yet
I think such difficulties have
little weight. |
|
| Here, as on other occasions, I lie under a heavy disadvantage,
out of the many striking cases which I have collected, I can give only one or two instances of transitional habits and structures in
→of the same genus;
and of diversified habits, either constant or occasional, in the same species. And it seems to me that nothing less than a long list of such cases is sufficient to lessen the difficulty in any particular case like that of the bat. |
|
| Look at the family of squirrels; here we have the finest gradation from animals with their tails only slightly flattened, and from others, as Sir J. Richardson has remarked, with the posterior part of their bodies rather wide and with the skin on their flanks rather full, to the so-called flying squirrels; and flying squirrels have their limbs and even the base of the tail united by a broad expanse of skin, which serves as a parachute and allows them to glide through the air to an astonishing distance from tree to tree. We cannot doubt that each structure is of use to each kind of squirrel in its own country, by enabling it to escape birds or beasts of prey,
to collect food more quickly, or, as there is reason to believe,
the danger from occasional falls. But it does not follow from this fact that the structure of each squirrel is the best that it is possible to conceive under all
conditions. Let the climate and vegetation change, let other competing
|
