DR. J. CLELAND ON THE VARIATIONS OE THE HUMAN SKULL. 
1GT 
is between the mastoid processes. Plainly, in this case, the deficient cerebral develop- 
ment is the cause and not the consequence of the form of the skull. 
Artificial deformities . — Among the American skulls examined three have been sub- 
jected to considerable artificial pressure. Of these, the Peruvian, 79, is the least 
deformed, and the writer has deemed it not unfair to use it in drawing up tables of 
national peculiarities. One of the other two (95) has been tightly compressed with 
bandages, while the other (96) has been flattened by boards not interfering with supple- 
mental lateral projection. A study of these two skulls shows some important points. 
In the flattened skull the proportion of the arch to the base is smaller than in any other 
skull examined, which, taken in conjunction with the circumstance that the base is a 
pretty short one, renders it probable that the growth of the roof-bones has been inter- 
fered with ; but in the other skull, in which the transverse and longitudinal diameters 
have been equally compressed, there is no evidence of any obstruction to the growth in 
length of the roof-bones. It does not appear that any arrest in the growth of the base 
has taken place in either skull. No doubt the orbits are shallow, but they are not un- 
naturally so ; and if it had happened that the development of the frontal sinuses at the 
proper period had been prevented by pressure in infancy, a thing in itself unlikely, there 
would have resulted from this, and indeed from any restraint of the normal growth 
forwards of the frontal bone, a large orbito-nasal angle consequent on the unrestrained 
natural growth forwards of the lower part of the jaw; but the orbito-nasal angle does 
not surpass 90° in either skull. The base in both skulls is very level and deficient in 
cranial curvature ; and both these peculiarities are best marked in the flattened skull, 
in which also the arch is most deformed. The deformity of the arch longitudinally 
consists in flattening of the frontal and occipital bones and bending of the parietals, as 
exhibited by the large midfrontal and midoccipital angles and small midparietal angle. 
Now this deformity of arch results from the cerebral mass being pressed out from the 
grasp of the compressing agent, and this grasp presses as much downwards as upwards ; 
and although it meets with more resistance in the downward than the upward direction, 
the effect of the downward pressure is exhibited in the levelness of the base and the 
deficient cranial curvature, — the action being, in fact, precisely of the same description 
as has been already mentioned as occurring in the large Greek skull 46. 
It is not, however, to be forgotten that, as has been pointed out by Professor Turner*, 
such skulls as these are not subjected to pressure during the whole period of growth, but 
owe their deformity to pressure in infancy ; and the question remains, how it happens 
that the deformed shape given to the infantile skull is preserved. Professor Turner 
suggests arrest of development from premature synostosis as the explanation, and his 
own observations, together with those of Dr. Daniel Wilson, show that in such skulls 
there is great tendency to obliteration of sutures ; while the flattened skull 96 gives an 
instance of arrest of development of the roof-bones. But it is difficult to see how syn- 
ostosis, although it may occur, accounts for the phenomena sought to be explained. To 
* Natural-History Review, 1864, p. 106, 
