206 
THE DESCENT OF MAN. 
j Part I. 
been derived. We should thus be justified in believing 
that at an extremely remote period a group of animals 
existed, resembling in many respects the larvae of our 
present Ascidians, which diverged into two great 
branches— the one retrograding in development and 
producing the present class of Ascidians, the other rising 
to the crown and summit of the animal kingdom by 
giving birth to the Vertebrata. 
We have thus far endeavoured rudely to trace the 
genealogy of the Vertebrata by the aid of their mutual 
affinities. We will now look to man as he exists ; and 
we shall, I think, be able partially to restore during 
successive periods, but not in due order of time, the 
structure of our early progenitors. This can be effected 
by means of the rudiments which man still retains, by 
the characters which occasionally make their appear- 
ance in him through reversion, and by the aid of the 
principles of morphology and embryology. The various 
facts, to which I shall here allude, have been given in 
the previous chapters. The early progenitors of man 
were no doubt once covered wdth hair, both sexes 
having beards ; their ears were pointed and capable of 
movement ; and their bodies were provided with a tail, 
having the proper muscles. Their limbs and bodies 
were also acted on by many muscles which now r 
only occasionally reappear, but are normally present 
in the Quadrumana. The great artery and nerve of 
the humerus ran through a supra-condyloid foramen. 
At this or some earlier period, the intestine gave forth 
a much larger diverticulum or csecum than that now 
existing. The foot, judging from the condition of the 
great toe in the foetus, was then prehensile; and our 
progenitors, no doubt, were arboreal m their habits, 
frequenting some warm, forest-clad and. The males 
