124 
THE VOYAGE OF H.M.S. CHALLENGER. 
of the vault of the several crania, except that of the Australian in the last column, has 
been given in the previous Tables under their respective headings, the relation as 
regards the relative length of the one to the other can be easily computed. Of the 
Australian skull, a male above referred to as excepted, I possess only one half, so that I 
have not included it in either Tables III. or IV., but I may state here that its total 
longitudinal arc is 374 mm. — the frontal 130 mm., parietal 125 mm., occipital 119 mm. 
The chords of the frontal, parietal, and occipital arcs are also recorded in Table XIX. 
As Dr. Cleland has pointed out in his paper on the Sulu skull, the occipital arc possesses 
in dolichocephalic skulls a very pronounced curvature. The contrast between the 
curvature of that bone in the dolichocephali figured in Plates VI. and VII., and the 
corresponding bone in the brachycephalic Hawaian is very marked. There is obviously 
no relation between the length of the basi-occipito-sphenoid axis, and either the absolute 
length of the skull or its length relatively to its breadth. Thus this axis in the brachy- 
cephalic Hawaian varied only one millimetre in length from the same axis in the 
dolichocephalic Fuegian, Admiralty Islander, and skull from Oahu, and only 2 mm. from 
one of the dolichocephalic Australians, a result which accords with the observations 
made by Prof. Huxley on his two widely contrasted forms of skulls. As regards the 
relations of the transverse diameters of the side walls of the skull to the length of this 
axis, it will be seen that the Stephanie and parietal diameters were greater in the 
Hawaian than in the Admiralty Islander, Fuegian, and Oahuan, but that the asterionic 
diameter, though greater in the Hawaian than in the Oahuan, was less in it than in 
the Fuegian and Admiralty Islander. It would seem therefore as if in brachycephalic 
as compared with dolichocephalic crania, a greater transverse growth took place in the 
frontal and parietal regions than in the occipital. The degree of what Prof. Huxley 
calls the anterior and posterior cerebral overlap may also readily be determined with the 
aid of the sectional diagrams in PI. VI. and VII., and the posterior overlap is obviously 
less in the brachycephalic than in the dolichocephalic skulls. 
I may supplement the remarks made in the Introduction on the method of taking the 
cranial capacity by stating that in the comparative measurements of each skull made by 
Mr. Jas. Simpson and myself, our measurements corresponded twenty-two times ; on 
twenty-three occasions the difference between us was 10 cc., and in the remaining 
seventy-four the difference was between 2 and 8 cc. I think therefore it may fairly be 
assumed that any two persons carefully carrying out a series of observations on the 
cubic capacity in the manner I have recommended, ought to arrive at results closely 
corresponding with each other, which may be taken as giving a fair approximation of 
the internal capacity of the crania examined. The series of observations showed very 
decidedly that in these savage people the mean cubic capacity of the female skull was 
distinctly below the male. 
Although my Tables do not record the breadth as well as the length of the foramen 
