| → duck. 1859 1860 1861 1866 1869 |
| duck: it is a remarkable fact that the young birds, according to Mr. Cunningham, can fly, while the adults have lost this power. 1872 |
|
| → I believe 1859 1860 1861 1866 1869 |
| it is probable 1872 |
|
| → from 1859 1860 1861 1866 1869 |
| by kicking its 1872 |
|
| → of the smaller 1859 1860 1861 1866 1869 |
| OMIT 1872 |
|
| → natural selection increased in successive generations 1859 1860 1861 1866 1869 |
| OMIT 1872 |
|
| → its 1859 1860 1861 1866 1869 |
| were increased during successive generations, its 1872 |
|
| → not quite decisive; 1866 1869 |
| very scanty; 1861 |
| not decisive; 1872 |
|
| → of epilepsy produced by injuring the spinal chord of guinea-pigs, being inherited, 1861 1866 |
| of inherited epilepsy in guinea-pigs, caused by an operation performed on the spinal chord, 1869 |
| in guinea-pigs, of the inherited effects of operations, 1872 |
|
| → cautious in denying such power. 1866 1869 |
| cautious. 1861 |
| cautious in denying this tendency. 1872 |
|
|
by the effects of disuse. As Professor Owen has remarked, there is no greater anomaly in nature than a bird that cannot fly; yet there are several in this state. The logger-headed duck of South America can only flap along the surface of the water, and has its wings in nearly the same condition as the domestic Aylesbury
→duck. As the larger ground-feeding birds seldom take flight except to escape danger,
→I believe
that the nearly wingless condition of several birds,
now
or
lately inhabited several oceanic islands, tenanted by no beast of prey, has been caused by disuse. The ostrich indeed inhabits
and is exposed to danger from which it cannot escape by flight, but
it can defend itself
→from
enemies, as
as
→of the smaller
quadrupeds. We may
that the
progenitor of the ostrich
habits like those of
bustard, and
as
→natural selection increased in successive generations
the size and weight of its
→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
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
of the Egyptians, they are totally deficient. The evidence that accidental mutilations can be inherited is at present
→not quite decisive;
but the remarkable
observed by Brown-Séquard
→of epilepsy produced by injuring the spinal chord of guinea-pigs, being inherited,
should make us
→cautious in denying such power.
|
