TRAQUAIR ON THE ABNORMALITY OE THE PARIETAL BONES. 133 
parietal bone, which is larger by about one-fourth than the single 
bone of the opposite side. 
This cranium is therefore abnormal. 
1. In possessing three parietal bones instead of two. 
2. In the asymmetrical disposition of these bones—two being on 
one side, one on the other. 
3. The vault of the cranium is also asymmetrical, in this respect, 
that the double parietal bone of the right side is considerably larger 
than the single one of the left. 
The only other analogous case, 
of which I am at present aware, is 
one recorded by Yon Sommering.* 
He has described and figured, not a 
foetal, but an adult skull, apparently 
of a man between the ages of thirty 
and fifty, in which the parietal bones 
of both sides are divided by longitu¬ 
dinal sutures, each into two equal 
parts—making in all, four symmetri¬ 
cally disposed parietal bones. This 
skull then differs from my foetal one, 
in which there are only three such bones unsymmetrically disposed, 
and in which the two parts of the divided parietal bone are not 
equal, the upper piece being twice the size of the lower.f 
I may also state that the foetal head, the peculiarity of whose 
parietal bones I have just described, presented in a marked manner 
the condition of Split Palate. In the recent state the interior of the 
nasal fossae was completely visible on opening the mouth: and as 
regards the dried bones, the palate plates of the superior maxillary 
and palate bones are entirely deficient, the superior maxillary bone 
articulating with its fellow of the opposite side only in front, and by 
the part corresponding to the intermaxillary of the other mammalia. 
Purther than this the cranium presents nothing worthy of note. 
Explanation of the figure. Diameter one-half nat. size. 
A and B upper and lower pieces of the double bone of the right side. 
* Tiedemann und Treviranus, Zeitschrift fur Physiologie II. (1826). 
f Since the above notice has been in print, I have seen in Henle’s Anatomy, a 
reference to another similar case recorded by Gruber,—Abhandlungen aus der 
Menschl. und Yergl. Anatomie, s. 113. Unfortunately I have not yet had an 
opportunity of seeing this latter work. 
