| → From such 1866 1869 |
| From such special 1859 1860 1861 |
| Owing to such 1872 |
|
| → especially when including a division of labour during the different stages of development, as when a larva during one stage has to search for food, and during another stage has to search for a place of attachment, the 1866 |
| the 1859 1860 1861 1872 |
| especially when they imply a division of labour during the different stages of development, as when the same larva has during one stage to search for food, and has during another stage to search for a place of attachment, the 1869 |
|
| → OMIT 1866 1869 1872 |
| or active embryos 1859 1860 1861 |
|
| → and cases could be given of the larvæ of two species, or of two groups of species, differing much more from each other, than do their adult parents. 1866 |
| and cases could be given of the larvæ of two species, or of two groups of species, differing quite as much, or even more, from each other than do their adult parents. 1859 1860 1861 |
| and cases could be given of the larvæ of two species, or of two groups of species, differing more from each other than do the adults. 1869 |
| especially when there is a division of labour during the different stages of development, as when the same larva has during one stage to search for food, and during another stage has to search for a place of attachment. 1872 |
|
|
The points of structure, in which the embryos of widely different animals
the same class resemble each other, often have no direct relation to their
of existence. We cannot, for instance, suppose that in the embryos of the vertebrata the peculiar loop-like
of the arteries near the branchial slits are related to similar conditions,— in the young mammal which is nourished in the womb of its mother, in the egg of the bird which is hatched in a nest, and in the spawn of a frog under water. We have no more reason to believe in such a relation, than we have to believe that the
bones in the hand of a man, wing of a bat, and fin of a porpoise, are related to similar conditions of life. No
that the stripes on the whelp of a lion, or the spots on the young blackbird, are of
use to these
|
|
| The case, however, is different when an animal during any part of its embryonic career is active, and has to provide for itself. The period of activity may come on earlier or later in life; but whenever it comes on, the adaptation of the larva to its conditions of life is just as perfect and as beautiful as in the adult animal. In how important a manner this has acted, has recently been well shown by Sir J. Lubbock in his remarks on the close similarity of the larvæ of some insects belonging to
different orders, and on the dissimilarity of the larvæ of other insects
the same order, according to their habits of life.
→From such
adaptations,
→especially when including a division of labour during the different stages of development, as when a larva during one stage has to search for food, and during another stage has to search for a place of attachment, the
similarity of the larvæ
→OMIT
of allied animals is sometimes
obscured;
→and cases could be given of the larvæ of two species, or of two groups of species, differing much more from each other, than do their adult parents.
|
