M. L. TiLDESLEY 
185 
d. Of the 53 male skulls, where the inion as defined by Mei kel could be deter- 
mined, it lay in 21 on the common horizontal tangent* to the lineae superiores, in 
17 rather below, in 15 above. 
In the 58 female skull°, it lay on the common tangent in 37 cases, in 9 below, 
in 12 above. Its average position in my series is evidently therefore at the point 
where the median plane cuts the commoii horizontal tangent to the lineae nuchae 
superiores. 
e. The lineae superiores also short-circuited sometimes, and formed a misleading 
ridge along their common tangent, as well as being continued V-wise to a point 
below in the normal manner. 
/. Where I found an inion projecting from the skull in a downward direction 
to form a hook, into which both the lineae supremae and Uneae superiores are 
continued, it was possible to detect the spot at which the Uneae supremae stopped 
short of the others. When such a skull was regarded in profile, the curve down- 
wards towards the tip of the hook showed a slight break at this point. 
Having made these general observations upon my 53 and 58 ? skulls, I made 
use of any that might serve to elucidate the system of lines upon my doubtful 
skulls, determining the inion by d where there was nothing to indicate for it 
another position. 
With reference to the very considerable variations in form of the inion, I cjuote 
Le Doublef: "II pent etre remplace par une depression, faire defaut, ou constitue 
par une eminence, lisse ou rugueuse, mamelonnee ou reccurbee en crochet a som- 
met inferieur," adding that only in one case in our whole series of 141 possessing 
the inionic region is the inion (dearly replaced by a depression. 
5. CONTOUES. 
A study was made of the three chief contours. Transverse, Horizontal, Sagittal. 
The contours were drawn by means of the Klaatsch contour tracer in the manner 
described by Dr Benington in his paper on Cranial Type Contours^. From certain 
average measurements on these were constructed type contours for each of the 
three racial classes we were dealing with. The method employed was as follows: 
(a) The Transverse (vertical or auricular coronal) Section. The slcull being 
placed on the craniophor and adjusted in the usual manner to the standard hori- 
zontal plane, the horizontal rod of the craniophor determines the "apex" of the 
skull, which is marked with a pencil stroke. Short lines are also drawn on the 
skull just above the auricular passages, and in the same vertical plane as the 
middle of the ear-rods, leading into the auricular passages, and meeting the little 
horizontal lines by which the position of the aiiricular points has been marked. 
The skull being now transferred to the Klaatsch apparatus, the vertical plane is 
made horizontal, and the contour traced from as far into the orifice as the pointer 
* That is, the tangent perpendicular to the sagittal plane. 
t Variations des Os du Crdne, p. 12. J Biometrika, Vol. vm. p. 123. 
