CH A P T E R II
TH E VARIOUS MEASUREMENTS EMPLOYED AND TH E METHOD
OF MAKING THEM
T h e selection of the various measurements employed in cataloguing the present
series of crania has been to some extent determined by the force of circumstances. Of
the 1,500 odd specimens embodied in the present report only some 200 are now
accessible. The majority of the skulls were measured on the site of excavation. Under
these conditions it was hopeless to expect so detailed a mensuration as might be executed
in a laboratory; it became important therefore to reduce the number of measurements to
such a minimum as would provide the data for general comparisons only. In this respect
perhaps there is matter for congratulation, since inquiries of this sort have been frequently
overloaded with endless columns of figures, ample evidence, no doubt, of the diligence and
application of the observer, but of questionable value, since up to the present they have
led to no useful or satisfactory results.
Absolute The absolute measurements recorded in the Appendix (see inset, pp. 1-32)
meats.16" include the following expressed in millimetres :—
1. Glabello-occipital length.
2. Ophryo-occipital length.
3. Basi-bregmatic height.
4. Maximum breadth.
5. Biauricular breadth.
6. Bizygomatic breadth.
7. Basi-nasal length.
8. Basi-alveolar length.
9. Nasi-alveolar height.
10. Nasal height.
11. Nasal width.
Little need be said regarding the method of taking these measures. The ophryo-
occipital length was included with the intention of being able to estimate to some extent
the superciliary projection; but we are alive to the difficulty of locating such a point as
the ophryon, and we question very much the practical value of this diameter. The idea
that it marks more precisely the boundary between the regions of the face and vault is in
our opinion untenable, since the superciliary projection depends not so much on structural
differences in the architecture of the face as on the imperfect expansion of the cranial cavity'.
Little or no attempt has been made in the present inquiry to correlate the glabello-
occipital and ophryo-occipital lengths, but since both were taken, both have been given in
the catalogue published in the Appendix. The other measures are so universally recognized
that no remarks need be made concerning them, other than to point out that the data
supplied furnish us with the material for broadly estimating by means of the resulting
indices the relative proportions of the calvaria and face.
1 See J o u rn a l o f th e A n thropologica l In stitu te, vol. xxxiii, 1903, pp. 135- 166.
MEASUREMENTS EMPLOYED AND METHOD OF MAKING THEM 35
From the absolutes given, the cephalic, vertical, upper facial, nasal, and gnathic indices,
indices have been computed. These are not recorded in the catalogue referred to, except
in the case of the gnathic index, to which reference will be presently made, but may be
ascertained by reference to the frequency-curves printed as separate sheets in the
Supplement. There, in each series, the reader will be able to ascertain the index of any given
skull, by searching for its catalogue-number within the frequency-curve of the given period,
where the skulls will be found arranged in numerical order over the indices to which they
correspond.
In regard to prognathism, we were early led to a consideration of the necessity of Orientation
orienting the skull in such a way as to enable us to compare with iair accuracy tne relative obtain a true
projection of the face in different specimens. the profec-
The orientation of the skull is no easy matter. As Professor Cleland said some don of the
thirty years ago, * It is quite likely that it will always be impossible to determine from the
characters of the skull what was its precise position in the erect position of the body/
Up to the present the problem remains unsolved, and though many suggestions have been
made, yet all seem open to objections of a more or less serious nature.
The Frankfort-Munich plane, that most commonly adopted by modem craniometrists,
whilst convenient to use for the rough comparison of crania, is open to serious objection if
employed in association with other cranial measurements and projections ; both the position
of the external auditory meatus and the inferior orbital margin are liable to very
considerable variations, the former by a
flattening of the cranial base, the latter
by its ascent or descent according as the
orbital index varies from microseme to
megaseme, for from a series of observations
which have been undertaken1 it
appears that the lower orbital margin is
liable to alter its position much more than
the superior orbital border. In a series
of thirty-eight skulls, which were selected
on account of their variety of orbital
forms, it appeared that there was a difference
of as much as 13 mm. in the level of the lower orbital margin. It will be easily understood
how such an alteration in the position of the inferior border leads to very grave
alterations in the orientation of the skull: the accompanying diagram will at once serve
to make this point clear. Another objection to the Frankfort-Munich plane, which
in practice is found to be somewhat serious, is the fact that the points selected are not
points from which any of the other measurements of the skull are taken (the transverse
arc alone excepted); hence the line is of little or no use as a base on which to reconstruct
the skull from the data usually given. Moreover, the fact that the plane is made to
pass through points which lie lateral to the mesial plane is another disadvantage, as
it prevents the orientation of profile outlines of the skull either from mesial sections
or orthographic tracings. It is with the object of overcoming these difficulties that
we have sought for some more satisfactory method of orienting the skull. The highly
suggestive paper of Huxley2 seems to us to embody methods which have a morphological
significance and are therefore of much greater value than the arbitrarily selected
1 See Appendix, p. 124. 1 J o u rn a l o f Anatom y and P h y siology , 1867.
F 2