184 
A First Study of the Burmese Sl iill 
4. Determination of the Inion. 
The determination of the inion has been discussed by more than one dis- 
tinguished craniometrician and anatomist; it has been dealt with in our own bio- 
metric school in a paper by M. A. Lewenz and K. Pearson* in the course of an 
argument which demonstrated its unsuitability as terminal for an arc measure- 
ment on the living, and which therefore was concerned to emphasise the very 
real difficulties in identifying this point, rather than to make any constructive 
suggestions as to the method of doing so. 
If I venture to take up this subject again, the circumstance is accounted for 
by the fact that the position of the inion still had to be marked on my sagittal 
contours, in spite of the difficulties. 
To recapitulate briefly: the original definition of the inion by Broca and in the 
Frankfurt Verstandigung, as the meeting-place of the lineae nuchae superiores, was 
abandoned generally by later scientists, Merkelf pointing out that the inion corre- 
sponded to the meeting-place of the lineae nuchae supreniae. 
I was able to identify a point which accorded with this later definition in 53 
of my male skulls; in seven it was vague; and of one I have only the skull-cap 
sawn off above the inionic region. In female skulls the inion is of course usually 
less pronounced, and the point as defined could be determined in only 58 out of 
74 cases. These numbers may be compared with those given by Professor ThaneJ 
where the inion could be determined in 41 out of 43 ^ and 43 out of 60 9 English 
skulls. The seven infant skulls in the Burmese collection naturally have little to 
indicate its position. 
I was thus left with 7 (J, 16 ? and 7 infant skulls, for which the position corre- 
sponding to this same anatomical point had to be inserted in my contours, within 
as narrow Mmits of accuracy as could be achieved. 
As a guide in doing this, I examined the skulls of my series in which the inion 
is to be found by Merkel's definition, and noted the following facts with regard 
to them: 
a. The lineae supremae are frequently very vague, even untraceable, although 
their juncture may be clear and prominent. 
h. The lineae superiores are usually, though by no means invariably, more 
clearly marked; their junction is generally recognisable, and in all cases in my 
collection where this is so, they are seen to curve downwards into a V before 
meeting. 
c. The lineae supremae, when descending to form a U about the median plane, 
as is often the case, occasionally short-circuit as well, giving an upper ridge with a 
shght depression between that and the lower junction which is our inion. This 
may be misleading at first if the inion be not boldly marked. 
* Biometrika, Vol. in. p. 375. 
t "Die Linea nuchae Suprema," Leipzig, 1871. Quoted by Scliwalbe, Zeitschrift fur Morphologie 
unci Aiithropologie, Vol. i. jj. 24, 1899. 
X Biometrika, Vol. m. p. 376. 
