d South America, of Africa and Asia
has brought to light many chapters in the history of life, which are
astonishingly full and complete. The flood of new material continues to
accumulate at such a rate that it is impossible to keep abreast of it,
and the very wealth of the collections is a source of difficulty and
embarrassment. In modern palaeontology phylogenetic questions and
problems occupy a foremost place and, as a result of the labours of many
eminent investigators in many lands, it may be said that this science
has proved to be one of the most solid supports of Darwin's theory.
True, there are very many unsolved problems, and the discouraged worker
is often tempted to believe that the fossils raise more questions than
they answer. Yet, on the other hand, the whole trend of the evidence
is so strongly in favour of the evolutionary doctrine, that no other
interpretation seems at all rational.

To present any adequate account of the palaeontological record from the
evolutionary standpoint, would require a large volume and a singularly
unequal, broken and disjointed history it would be. Here the record is
scanty, interrupted, even unintelligible, while there it is crowded with
embarrassing wealth of material, but too often these full chapters are
separated by such stretches of unrecorded time, that it is difficult to
connect them. It will be more profitable to present a few illustrative
examples than to attempt an outline of the whole history.

At the outset, the reader should be cautioned not to expect too
much, for the task of determining phylogenies fairly bristles with
difficulties and encounters many unanswered questions. Even when the
evidence seems to be as copious and as complete as could be wished,
different observers will put different interpretations upon it, as in
the notorious case of the Steinheim shells. (In the Miocene beds of
Steinheim, Wurtemberg, occur countless fresh-water shells, which show
numerous lines of modification, but these have been very differently
interpreted by different writers.) The ludicrous discrepances which
often appear between the phylogenetic "trees" of various writers have
cast an undue discredit upon the science and have led many zoologists
to ignore palaeontology altogether as unworthy of serious attention. One
principal cause of these discrepant and often contradictory results is
our ignorance concerning the exact modes of developmental change.
What one writer postulate