And here you have
the hinder limbs restored in the shape of these ventral fins. If I
were to make a transverse section of this, I should find just the same
organs that we have before noticed. So that, you see, there comes out
this strange conclusion as the result of our investigations, that the
Horse, when examined and compared with other animals, is found by no
means to stand alone in nature; but that there are an enormous number
of other creatures which have backbones, ribs, and legs, and other
parts arranged in the same general manner, and in all their formation
exhibiting the same broad peculiarities.
I am sure that you cannot have followed me even in this extremely
elementary exposition of the structural relations of animals, without
seeing what I have been driving at all through, which is, to show you
that, step by step, naturalists have come to the idea of a unity of
plan, or conformity of construction, among animals which appeared at
first sight to be extremely dissimilar.
And here you have evidence of such a unity of plan among all the
animals which have backbones, and which we technically call
"Vertebrata".
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