The embryos, also, of distinct animals within the same class are often strikingly similar: a better proof of this cannot be given, than a
statement made by Von Baer, statement made by Von Baer, 1861 |
circumstance mentioned by Agassiz, 1859 1860 |
namely, that
"the "the 1861 |
having forgotten to ticket the 1859 1860 |
embryos embryos 1861 | embryo 1859 1860 |
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. 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. 1861 |
some vertebrate animal, he cannot now tell whether it be that of a mammal, bird, or reptile. 1859 1860 |
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." ↑1 blocks not present in 1859 1860 1861 1866 1869; present in 1872 | The larvæ of most crustaceans, at corresponding stages of development, closely resemble each other, however different the adults may become; and so it is with very many other animals.
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The vermiform larvæ of moths, flies, beetles,
&c., &c., 1859 1860 1861 1869 | &, 1866 |
resemble resemble 1859 1860 1861 | generally resemble 1866 1869 |
each other much more closely than do the mature insects; but in
the the 1859 1860 1861 1866 | these 1869 |
case case 1859 1860 1861 1866 | cases 1869 |
of larvæ, of larvæ, 1859 1860 1861 1866 | of larvæ, 1869 |
the embryos are active, and
have have 1859 1860 1861 | from having 1866 1869 |
been adapted for special lines of
life. life. 1859 1860 1861 |
life sometimes differ much from each other. 1866 1869 |
A trace of the
law law 1859 1860 1861 1866 1872 | jaw 1869 |
of embryonic
resemblance, resemblance, 1859 1860 1861 1866 | resemblance 1869 1872 |
sometimes sometimes 1859 1860 1861 | occasionally 1866 1869 1872 |
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
first and second first and second 1859 1860 1861 1866 |
immature 1869 1872 |
plumage; as we see in the spotted feathers in the
thrush thrush 1859 1860 1861 1866 |
young of the thrush 1869 1872 |
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: 1859 1860 1861 1866 | plants; 1869 1872 |
thus the
first first 1861 1866 1869 1872 | embryonic 1859 1860 |
leaves of the ulex or furze, and the first leaves of the
phyllo- dineous phyllo- dineous 1861 | phyllodineous 1859 1860 1866 1869 1872 |
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