Comparison with 1860 |
|
quadrupeds. We may imagine
that the early
progenitor of the ostrich had
habits like those of a
bustard, and that
as natural selection increased in successive generations
the size and weight of its body,
its
legs were used more, and its wings less, until they became incapable of flight. |
|
Kirby has remarked (and I have observed the same fact) that the anterior tarsi, or feet, of many male dung-feeding beetles are very
often broken off; he examined seventeen specimens in his own collection, and not one had even a relic left. In the Onites apelles the tarsi are so habitually lost, that the insect has been described as not having them. In some other genera they are present, but in a rudimentary condition. In the Ateuchus or sacred beetle
of the Egyptians, they are totally deficient. ↑1 blocks not present in 1859 1860; present in 1861 1866 1869 1872 | The evidence that accidental mutilations can be inherited is at present very scanty;
but the remarkable case
observed by Brown-Séquard of epilepsy produced by injuring the spinal chord of guinea-pigs, being inherited,
should make us cautious. |
There is not sufficient evidence to induce me to believe that mutilations are ever inherited; and I should prefer explaining There is not sufficient evidence to induce me to believe that mutilations are ever inherited; and I should prefer explaining 1860 |
There is not sufficient evidence to induce us to believe that mutilations are ever inherited; and I should prefer explaining 1859 |
So that it will perhaps be safest to look at 1861 1866 |
Hence it will perhaps be safest to look at 1869 1872 |
the entire absence of the anterior tarsi in Ateuchus, and their rudimentary condition in some other genera, by the long-continued
effects of disuse in their progenitors;
for as the tarsi are almost always lost in
many dung-feeding beetles,
they must be lost
early in life,
and
therefore cannot
be much
used by these insects. |
|
In some cases we might easily put down to disuse modifications of structure which are wholly, or mainly, due to natural selection. Mr. Wollaston has discovered the remarkable fact that 200 beetles,
out of the 550 species inhabiting
Madeira,
are so far deficient in wings that they cannot fly; and that
of the twenty-nine endemic genera, no less than twenty-three genera
have all their species in this condition! Several facts,
namely,
that beetles in many parts of the world are
....... 1860 1861 1866 1869 1872 | very 1859 |
frequently blown to sea and perish; that the beetles in Madeira, as observed by Mr. Wollaston, lie much
....... 1860 1861 1866 1869 1872 | con- 1859 |
|
quadrupeds. We may
imagine imagine 1859 1860 | believe 1861 1866 1869 1872 |
that the
early early 1859 1860 | early 1861 1866 1869 1872 |
progenitor of the ostrich
had had 1859 1860 | genus had 1861 1866 1869 1872 |
habits like those of
a a 1859 1860 1861 1866 1869 | the 1872 |
bustard, and
that that 1859 1860 1861 | that, 1866 1869 1872 |
as
natural selection increased in successive generations natural selection increased in successive generations 1859 1860 1861 1866 1869 |
OMIT 1872 |
the size and weight of its
body, body, 1859 1860 1861 1866 1869 | body 1872 |
its its 1859 1860 1861 1866 1869 |
were increased during successive generations, its 1872 |
legs were used more, and its wings less, until they became incapable of flight. |
|
Kirby has remarked (and I have observed the same fact) that the anterior tarsi, or feet, of many male dung-feeding beetles are
very very 1859 1860 1861 1866 1869 | very 1872 |
often broken off; he examined seventeen specimens in his own collection, and not one had even a relic left. In the Onites apelles the tarsi are so habitually lost, that the insect has been described as not having them. In some other genera they are present, but in a rudimentary condition. In the Ateuchus or sacred
beetle beetle 1859 1860 1861 1869 1872 | bettle 1866 |
of the Egyptians, they are totally deficient. ↑1 blocks not present in 1859 1860; present in 1861 1866 1869 1872 | The evidence that accidental mutilations can be inherited is at present very scanty;
but the remarkable case
observed by Brown-Séquard of epilepsy produced by injuring the spinal chord of guinea-pigs, being inherited,
should make us cautious. |
There is not sufficient evidence to induce us to believe that mutilations are ever inherited; and I should prefer explaining There is not sufficient evidence to induce us to believe that mutilations are ever inherited; and I should prefer explaining 1859 |
There is not sufficient evidence to induce me to believe that mutilations are ever inherited; and I should prefer explaining 1860 |
So that it will perhaps be safest to look at 1861 1866 |
Hence it will perhaps be safest to look at 1869 1872 |
the entire absence of the anterior tarsi in Ateuchus, and their rudimentary condition in some other genera,
by the long-continued by the long-continued 1859 1860 |
as due to the long-continued 1861 1866 |
as due to the 1869 |
not as cases of inherited mutilations, but as due to the 1872 |
effects of
disuse in their progenitors; disuse in their progenitors; 1859 1860 1861 1866 |
long-continued disuse; 1869 1872 |
for as
the tarsi are almost always lost in the tarsi are almost always lost in 1859 1860 1861 1866 |
OMIT 1869 1872 |
many dung-feeding
beetles, beetles, 1859 1860 1861 1866 | beetles 1869 1872 |
they must be lost they must be lost 1859 1860 1861 1866 |
are generally found with their tarsi lost, this must happen 1869 1872 |
early in
life, life, 1859 1860 1861 1866 | life; 1869 1872 |
and and 1859 1860 1861 1866 | and 1869 1872 |
therefore
cannot cannot 1859 1860 1861 1866 |
the tarsi cannot be of much importance or 1869 1872 |
be
much much 1859 1860 1869 1872 |
of much importance or be much 1861 1866 |
used by these insects. |
|
In some cases we might easily put down to disuse modifications of structure which are wholly, or mainly, due to natural selection. Mr. Wollaston has discovered the remarkable fact that 200
beetles, beetles, 1859 1860 1866 1869 1872 | beetles 1861 |
out of the 550 species
inhabiting inhabiting 1859 1860 1861 |
(but more are now known) which inhabit 1866 1869 |
(but more are now known) inhabiting 1872 |
Madeira, Madeira, 1859 1860 1866 1869 1872 | Madeira 1861 |
are so far deficient in wings that they cannot fly; and
that that 1859 1860 1861 | that, 1866 1869 1872 |
of the twenty-nine endemic genera, no less than twenty-three
genera genera 1859 1860 1861 1866 1869 | genera 1872 |
have all their species in this condition! Several
facts, facts, 1859 1860 1861 1866 1869 | facts,— 1872 |
namely, namely, 1859 1860 1861 1872 | — namely, 1866 1869 |
that beetles in many parts of the world are
very very 1859 | very 1860 1861 1866 1869 1872 |
frequently blown to sea and perish; that the beetles in Madeira, as observed by Mr. Wollaston, lie much
con- con- 1859 | con- 1860 1861 1866 1869 1872 |
|