The Descent of Man

in Todd's 'Cyclopaedia of Anatomy' 1849-52,
vol. iv. p. 1415. In man this organ is only from
three to six lines in length, but, like so many
other rudimentary parts, it is variable in development
as well as in other characters.) Some
other rudimentary structures belonging to the
reproductive system might have been here adduced.
(55. See, on this subject, Owen, 'Anatomy
of Vertebrates,' vol. iii. pp. 675, 676, 706.)
The bearing of the three great classes of facts
now given is unmistakeable. But it would be
superfluous fully to recapitulate the line of argument
given in detail in my 'Origin of Species.'
The homological construction of the whole
frame in the members of the same class is
intelligible, if we admit their descent from a
common progenitor, together with their subsequent
adaptation to diversified conditions. On
any other view, the similarity of pattern between
the hand of a man or monkey, the foot of
a horse, the flipper of a seal, the wing of a bat,