The Descent of Man

genus, whilst the third line might become so
greatly modified as to deserve to rank as a distinct
Sub-family, Family, or even Order. But in
this case it is almost certain that the third line
would still retain through inheritance numerous
small points of resemblance with the other
two. Here, then, would occur the difficulty, at
present insoluble, how much weight we ought
to assign in our classifications to stronglymarked
differences in some few points,—that
is, to the amount of modification undergone;
and how much to close resemblance in numerous
unimportant points, as indicating the lines
of descent or genealogy. To attach much weight
to the few but strong differences is the most
obvious and perhaps the safest course, though
it appears more correct to pay great attention to
the many small resemblances, as giving a truly
natural classification.
In forming a judgment on this head with reference
to man, we must glance at the classifica-