284 THE AMERICAN NATURALIST. . [Vor. XXXVI. 
Both Gruber’s and Virchow’s opinions gained adherents, and 
in the absence of decisive embryological investigation the matter 
is still unsettled. 
The significance of the partial malar divisions can be actually 
demonstrated only by studies on the embryo. Nevertheless, 
the examination of older subjects brings out a few points from 
which, it seems to me, it is possible to draw a few deductions 
having a bearing on the nature of these divisions. 
Such points are the size of the incisures, their somewhat 
greater frequency in childhood than in adult life, and the lack 
of correspondence in frequency between the incomplete and 
complete divisions in childhood in general or in the adults of 
different ethnic groups. 
All the points mentioned speak against an exact equivalence 
of the partial and complete malar divisions and for Gruber’s 
theory. Were all or a majority of the incisures remnants of 
formerly complete separations of the malar, it is reasonable to 
suppose that we should, even if rarely, meet with a remnant of 
the separation that would extend over more than a half of the 
bone ; and it would be logical to expect a greater frequency of 
complete divisions in early than in later life and in those tribes 
or races in whom the incisures are more common than in others. 
As these conditions are not realized we must search for another 
explanation for the incisures. This explanation can be found, 
as already pointed out by Gruber, in the analogies of the devel- 
opment of the malar with other cranial bones, particularly the 
occipital, or the parietal. 
The parietal bone will, I think, serve the demonstration even 
better than the occipital. The bone develops, as was shown by 
Toldt and Ranke, from two superimposed centers of ossifica- 
tion, — a very. similar process to that which undoubtedly takes 
place in the body of the malar, though this bone may possibly 
develop from more than two original points. The two centers 
of the parietal have but a very brief separate existence. They 
grow in all directions and very soon coalesce, Their union 
takes place at their reciprocally most advanced portions, in the 
middle, the parts anterior and posterior to this point of fusion 
e D 3) | 
pa by a more or less V-shaped space or fissure. 

