| → or more necessary, 1859 1860 1861 1866 1869 |
| or, in order fully to understand the relations of the parts, more useful 1872 |
|
| → in order fully to understand the relations of the parts, than the 1869 |
| than the use and 1859 1860 1861 1866 |
| than the 1872 |
|
| → leg of the 1859 1860 1861 1866 1869 |
| OMIT 1872 |
|
| → relatively to the adjoining parts in the embryo, 1859 1860 1861 1866 1869 |
| in the embryo relatively to the adjoining parts, 1872 |
|
|
In tracing the homologies of
part in different
of
class, nothing is more common,
→or more necessary,
→in order fully to understand the relations of the parts, than the
discovery of rudiments. This is well shown in the drawings given by Owen of the
of the
→leg of the
horse, ox, and rhinoceros. |
|
| It is an important fact that rudimentary organs, such as teeth in the upper jaws of whales and ruminants, can often be detected in the embryo, but afterwards wholly disappear. It is also, I believe, a universal rule, that a rudimentary part
is of greater size
→relatively to the adjoining parts in the embryo,
than in the adult; so that the organ at this early age is less rudimentary, or even cannot be said to be in any degree rudimentary.
rudimentary
in the
often said to have retained
embryonic condition. |
|
| I have now given the leading facts with respect to rudimentary organs. In reflecting on them, every one must be struck with
for the same reasoning power which tells us
that most parts and organs are exquisitely adapted for certain purposes, tells us with equal plainness that these rudimentary or atrophied
are imperfect and useless. In works on natural
rudimentary organs are generally said to have been created "for the sake of symmetry," or in order "to complete the scheme of
But this is not an explanation, merely a re-statement of the fact. Nor is it consistent with itself: thus the boa-constrictor has rudiments of hind-limbs and of a pelvis, and if it be said that these bones have been retained "to complete the scheme of nature," why, as Professor Weismann asks, have they not been retained by other snakes, which do not possess even a vestige of these same
|
