roups, are not to be found anywhere in the
records of the past history of the globe, their absence is a strong and
weighty negative argument against evolution; while, on the other hand,
if such intermediate forms are to be found, that is so much to the good
of evolution; although, for reasons which I will lay before you by and
by, we must be cautious in our estimate of the evidential cogency of
facts of this kind.

It is a very remarkable circumstance that, from the commencement of the
serious study of fossil remains; in fact, from the time when Cuvier
began his brilliant researches upon those found in the quarries of
Montmartre, palaeontology has shown what she was going to do in this
matter, and what kind of evidence it lay in her power to produce.

I said just now that, in the existing Fauna, the group of pig-like
animals and the group of ruminants are entirely distinct; but one of the
first of Cuvier's discoveries was an animal which he called the
_Anoplotherium_, and which proved to be, in a great many important
respects, intermediate in character between the pigs, on the one hand,
and the ruminants on the other. Thus research into the history of the
past did, to a certain extent, tend to fill up the breach between the
group of ruminants and the group of pigs. Another remarkable animal
restored by the great French palaeontologist, the _Palaeotherium_,
similarly tended to connect together animals to all appearance so
different as the rhinoceros, the horse, and the tapir. Subsequent
research has brought to light multitudes of facts of the same order;
and, at the present day, the investigations of such anatomists as
Ruetimeyer and Gaudry have tended to fill up, more and more, the gaps in
our existing series of mammals, and to connect groups formerly thought
to be distinct.

But I think it may have an especial interest if, instead of dealing with
these examples, which would require a great deal of tedious osteological
detail, I take the case of birds and reptiles; groups which, at the
present day, are so clearly distinguished from one another that there
are perhaps no classes of animals which, in popular apprehension, are
more completely separated. Existing birds, as you are aware, are covered
with feathers; their anterior extremities, specially and peculiarly
modified, are converted into wings, by the aid of which most of them are
able to fly; they walk upright upon two legs; and these limbs, when they
are consider