namely, namely, 1866 1869 | namely, 1872 |
that "the embryos of mammalia, of birds, lizards, and snakes, probably also of chelonia, are in their earliest states exceedingly like one another, both as a whole and in the mode of development of their parts; so much so, in fact, that we can often distinguish the embryos only by their size. ↑1 blocks not present in 1866 1869 1872; present in 1859 1860 1861 | The embryos, also, of distinct animals within the same class are often strikingly similar: a better proof of this cannot be given, than a circumstance mentioned by Agassiz,
namely, that having forgotten to ticket the
embryo
of some vertebrate animal, he cannot now tell whether it be that of a mammal, bird, or reptile.
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In my possession are two little embryos in spirit, whose names I have omitted to attach, and at present I am quite unable to say to what class they belong. They may be lizards or small birds, or very young mammalia, so complete is the similarity in the mode of formation of the head and trunk in these animals. The extremities, however, are still absent in these embryos. But even if they had existed in the earliest stage of their development we should learn nothing, for the feet of lizards and mammals, the wings and feet of birds, no less than the hands and feet of man, all arise from the same fundamental form."
The vermiform larvæ of moths, flies, beetles,
&c., &c., 1859 1860 1861 1869 | &, 1866 |
generally resemble generally resemble 1866 1869 | resemble 1859 1860 1861 |
each other much more closely than do the mature insects; but in
these these 1869 | the 1859 1860 1861 1866 |
cases cases 1869 | case 1859 1860 1861 1866 |
....... 1869 | of larvæ, 1859 1860 1861 1866 |
the embryos are active, and
from having from having 1866 1869 | have 1859 1860 1861 |
been adapted for special lines of
life sometimes differ much from each other. life sometimes differ much from each other. 1866 1869 |
life. 1859 1860 1861 |
A trace of the
jaw jaw 1869 | law 1859 1860 1861 1866 1872 |
of embryonic
resemblance resemblance 1869 1872 | resemblance, 1859 1860 1861 1866 |
occasionally occasionally 1866 1869 1872 | sometimes 1859 1860 1861 |
lasts till a rather late age: thus birds of the same genus, and of
closely closely 1859 1860 1861 1866 1869 | closely 1872 |
allied genera, often resemble each other in their
immature immature 1869 1872 |
first and second 1859 1860 1861 1866 |
plumage; as we see in the spotted feathers in the
young of the thrush young of the thrush 1869 1872 |
thrush 1859 1860 1861 1866 |
group. In the cat tribe, most of the species
are are 1859 1860 1861 1866 1869 |
when adult are 1872 |
striped or spotted in lines; and stripes
or spots can or spots can 1861 1866 1869 1872 |
can 1859 1860 |
be plainly distinguished in the whelp of the
lion and the puma. lion and the puma. 1861 1866 1869 1872 |
lion. 1859 1860 |
We occasionally though rarely see something of
this this 1859 1860 1861 1866 1869 | the same 1872 |
kind in
plants; plants; 1869 1872 | plants: 1859 1860 1861 1866 |
thus the
first first 1861 1866 1869 1872 | embryonic 1859 1860 |
leaves of the ulex or furze, and the first leaves of the
phyllodineous phyllodineous 1859 1860 1866 1869 1872 | phyllo- dineous 1861 |
acacias, acacias, 1861 1866 1869 1872 | acaceas, 1859 1860 |
are pinnate or divided like the ordinary leaves of the
leguminosæ. leguminosæ. 1859 1861 1866 1869 1872 | leguminousæ. 1860 |
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