The Descent of Man

then be justified in believing that at an extremely
remote period a group of animals existed,
resembling in many respects the larvae of our
present Ascidians, which diverged into two
great branches—the one retrograding in development
and producing the present class of
Ascidians, the other rising to the crown and
summit of the animal kingdom by giving birth
to the Vertebrata.
We have thus far endeavoured rudely to trace
the genealogy of the Vertebrata by the aid of
their mutual affinities. We will now look to
man as he exists; and we shall, I think, be able
partially to restore the structure of our early
progenitors, during successive periods, but not
in due order of time. This, can be effected by
means of the rudiments which man still retains,
by the characters which occasionally make their
appearance in him through reversion, and by
the aid of the principles of morphology and
embryology. The various facts, to which I shall