50 THE STRUCTURE OF MAN 
essential importance for us here is the fact that the skull of Man 
and all Vertebrates is constructed on a common plan (ef. A and 
IB hie IL 
The fact that this ground plan is not so evident in the skull 
of the higher Vertebrata and Man as in that of the lower Verte- 
brates, is due to the progressive modification which the former have 
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Fic. 32,—SKULL OF IMMANUEL Kant. (After C. von Kupffer.) 
(The great size of the cranium is a noteworthy feature. ) 
undergone; and the final result has been that the human skull 
differs markedly not only from that of the lower Vertebrata, but 
also from that of the Anthropoid Apes, which in the rest of their 
skeleton agree so closely with Man. It will, therefore, be interest- 
ing to examine the two latter types of skull, in order to determine © 
and, when possible, explain the differences between them. 
On mere superficial examination, the proportionate difference 
in size between the cranium and the face of the two is most 
striking. In Man (Fig. 32) the cranium is a smooth and imposing 
4 
