A, Hipparion; 7 and 7A, the modern horse. Note how the toes shorten and
disappear.]

[Illustration: A. Fore-limb of Monkey B. Fore-limb of Whale

WHAT IS MEANT BY HOMOLOGY? ESSENTIAL SIMILARITY OF ARCHITECTURE, THOUGH
THE APPEARANCES MAY BE VERY DIFFERENT

This is seen in comparing these two fore-limbs, A, of Monkey, B, of
Whale. They are as different as possible, yet they show the same bones,
e.g. SC, the scapula or shoulder-blade; H, the humerus or upper arm; R
and U, the radius and ulna of the fore-arm; CA, the wrist; MC, the palm;
and then the fingers.]

But in spite of man's undeniable apartness, there is no doubt as to his
solidarity with the rest of creation. There is an "all-pervading
similitude of structure," between man and the Anthropoid Apes, though it
is certain that it is not from any living form that he took his origin.
None of the anatomical distinctions, except the heavy brain, could be
called momentous. Man's body is a veritable museum of relics (vestigial
structures) inherited from pre-human ancestors. In his everyday bodily
life and in some of its disturbances, man's pedigree is often revealed.
Even his facial expression, as Darwin showed, is not always human. Some
fossil remains bring modern man nearer the anthropoid type.

It is difficult not to admit the ring of truth in the closing words of
Darwin's _Descent of Man_:

"We must, however, acknowledge, as it seems to me, that man, with
all his noble qualities, with sympathy which feels for the most
debased, with benevolence which extends not only to other men but to
the humblest living creature, with his God-like intellect which has
penetrated into the movements and constitution of the solar
system--with all these exalted powers--man still bears in his bodily
frame the indelible stamp of his lowly origin."

THE EVOLVING SYSTEM OF NATURE

There is another side of evolution so obvious that it is often
overlooked, the tendency to link lives together in vital
inter-relations. Thus flowers and their insect visitors are often
vitally interlinked in mutual dependence. Many birds feed on berries and
distribute the seeds. The tiny freshwater snail is the host of the
juvenile stages of the liver-fluke of the sheep. The mosquito is the
vehicle of malaria from man to man, and the tse-tse fly spreads sleeping
sickness. The freshwater mussel cannot continue its race without the
unconscious co-operation of the minnow, and the