| → on the common 1859 1860 1861 1866 1869 |
| in accordance with the old 1872 |
|
| → but, as Schiödte and others have remarked, 1859 1860 |
| OMIT 1861 1866 |
| OMIT 1869 1872 |
|
| → and the cave-insects of 1859 1860 |
| OMIT 1869 1872 |
| if we look at 1861 1866 |
|
| → continents are not more closely allied than might have been anticipated from the general resemblance of the other inhabitants of North America and Europe. 1859 1860 |
| OMIT 1869 1872 |
| whole faunas; and with respect to the insects alone, Schiödte has remarked, " 1861 1866 |
|
| ↑ 1 blocks not present in 1859 1860 1861 1866; present in 1869 1872 |
| This is certainly not the case if we look at the two whole faunas; and with respect to the insects alone, Schiödte has remarked,
|
|
| → ordinary 1859 1860 |
| in most cases ordinary 1861 1866 1869 1872 |
|
| → "animals 1859 1860 |
| "We accordingly look upon the subterranean faunas as small ramifications which have penetrated into the earth from the geographically limited faunas of the adjacent tracts, and which, as they extended themselves into darkness, have been accommodated to surrounding circumstances. Animals 1861 1866 1869 1872 |
|
| → darkness." 1859 1860 |
| darkness, and whose formation is quite peculiar." 1861 1866 1869 1872 |
|
|
to have increased the size of the eyes; whereas with all the other inhabitants of the caves, disuse by itself seems to have done its work. |
|
| It is difficult to imagine conditions of life more similar than deep limestone caverns under a nearly similar climate; so
→on the common
view of the blind animals having been separately created for the American and European caverns,
similarity in their organisation and affinities might have been
→but, as Schiödte and others have remarked,
→and the cave-insects of
→continents are not more closely allied than might have been anticipated from the general resemblance of the other inhabitants of North America and Europe.
↑ On my view we must suppose that American animals, having
→ordinary
powers of vision, slowly migrated by successive generations from the outer world into the deeper and deeper recesses of the Kentucky caves, as did European animals into the caves of Europe. We have some evidence of this gradation of habit; for, as Schiödte remarks,
→"animals
not far remote from ordinary forms, prepare the transition from light to darkness. Next follow those that are constructed for twilight; and, last of all, those destined for total
→darkness."
By the time that an animal had reached, after numberless generations, the deepest recesses, disuse will on this view have more or less perfectly obliterated its eyes, and natural selection will often have effected other changes, such as an increase in the length of the antennæ or palpi, as a compensation for blindness. Notwithstanding such modifications, we might expect still to see in the cave-animals of America, affinities to the other inhabitants of that continent, and in those of
to the inhabitants of the European continent. And this is the case with some of the American cave-animals, as I hear from
|
