contented myself by merely alluding to this belief. When I came to
apply this view to man, I found it indispensable to treat the whole
subject in full detail. (2. Prof. Haeckel was the only author who, at
the time when this work first appeared, had discussed the subject of
sexual selection, and had seen its full importance, since the
publication of the Origin ; and this he did in a very able manner in
his various works.) Consequently the second part of the present work,
treating of sexual selection, has extended to an inordinate length,
compared with the first part; but this could not be avoided.
I had intended adding to the present volumes an essay on the expression
of the various emotions by man and the lower animals. My attention was
called to this subject many years ago by Sir Charles Bell s admirable
work. This illustrious anatomist maintains that man is endowed with
certain muscles solely for the sake of expressing his emotions. As this
view is obviously opposed to the belief that man is descended from some
other and lower form, it was necessary for me to consider it. I
likewise wished to ascertain how far the emotions are expressed in the
same manner by the different races of man. But owing to the length of
the present work, I have thought it better to reserve my essay for
separate publication.
PART I.
THE DESCENT OR ORIGIN OF MAN.
CHAPTER I.
THE EVIDENCE OF THE DESCENT OF MAN FROM SOME LOWER FORM.
Nature of the evidence bearing on the origin of man Homologous
structures in man and the lower animals Miscellaneous points of
correspondence Development Rudimentary structures, muscles, sense-
organs, hair, bones, reproductive organs, etc. The bearing of these
three great classes of facts on the origin of man.
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