4 
THE VOYAGE OF H.M.S. CHALLENGER. 
the diameter from the mid-occipital point to the fronto-nasal suture (nasion), which is the 
dimension taken by Professors van der Hoeven, 1 Cleland 2 and Virchow, 3 for I find that 
as a rule it approximates to the ophryo-occipital diameter. In many specimens, more 
especially in female skulls, the difference between the ophryo-occipital, nasio-occipital and 
glabello-occipital diameters, does not amount to more than two or three millimetres, and 
it is only when a great development of the frontal air-sinuses and of the glabella takes 
place, that the difference in these three diameters becomes very distinctly marked. 
The greatest breadth recorded in the table is taken in the parietal or parieto-squamous 
region, wherever it occurs, and the letters p and s appended to the measurement express 
whether this maximum breadth be situated at or near the parietal eminence, or at or near 
the parieto-squamous suture. The greatest breadth and the glabello-occipital diameter 
have been taken therefore in the manner proposed by the illustrious Eetzius, 4 the founder 
of scientific craniometry. 
The length-breadth or cephalic-index has been calculated from the relations between 
the greatest breadth and the glabello-occipital length, 5 but those craniologists who desire 
to take the ophryo-occipital length as the basis of their calculation have the data 
furnished in the tables. I have preferred the glabello-occipital length as a basis for 
calculating the cephalic index, rather than the ophryo-occipital diameter, which has been 
adopted by Dr. Barnard Davis 6 and by Professors Kolleston 7 and Flower. 8 For the ophryon 
has not the same definite position as the glabella, and observers do not always agree in 
localising the ophryon at the same point on a skull. To ignore the glabella in estimating 
the extreme length of the cranium, is to leave out of consideration an eminence which in 
many skulls and heads constitutes one of the most noticeable features in the frontal region, 
and which is so frequently an important sexual character. Moreover, it seems to me that 
with the skull as with the living head, our object should be to compare the greatest length 
and greatest breadth with each other wherever they occur, and not to confine our measure- 
ments to those parts of the skull which more directly form the wall of the brain cavity. 
I have arranged the crania according to the proportions of length and breadth into 
three categories and have adopted M. Broca's term mesaticephalic, to express a group 
between the dolichocephalic and brachycephalic types of skull. 
I have not thought it necessary to adopt those minor subdivisions of sub-dolichocephalic 
1 Catalogus craniorum diversarium gentium, Leyden, I860. 
2 Variations of the human skull, &e., Phil. Trans., 1869. 3 Archivfiir Anthropologic, vol. iv. p. 59, 1870. 
4 Miillers Archiv, 1845, p. 126, and Ethnologische Schriften, pp. 24-166. 
5 The glabello-occipital length is merely another mode of expressing the diameter subsequently named by M. Broca, 
the antero-posterior maximum. 
6 Although Dr. Davis states that his measurement is taken from the glabella, yet as he regards that " as about an 
inch above the fronto-nasal suture," it obviously approximates closely to the ophryon. 
7 British Barrows, p. 560, 1877, and collected Scientific Papers and Addresses edited by Prof. Turner, p. 165, 
Oxford, 1884. 
8 Catalogue of Human Crania, p. xvii. 1879. 
