120 
THE VOYAGE OF H.M.S. CHALLENGER, 
was working at the anatomical relations of the tentorium to the cerebrum and cerebellum. 1 
The modifications in the thickness of the two tables and of the diploe of the bones of the 
cranial vault, and the extent of the frontal and sphenoidal sinuses are revealed in such 
sections. It is interesting to observe that the massive skull of the Chatham Islander and 
that of the New Zealander had no frontal sinus in the glabella ; in the Bush skull this 
sinus had both great vertical and lateral extension. 
In the first place, I have drawn from a common centre a number of radii to definite 
points on the surface in the mesial line of the outer table. The centre I have selected is 
the basion, to the importance of which I have already referred in the introduction to this 
Keport. I have also drawn a line in the plane of the foramen magnum and erected a 
Table XVIII. (Plates VI., VII.) 
Radii. 
Basi-oecipital, 
Bush. 
Umzim- 
kulu. 
94 
Fue- 
gian. 
D. 
108 
Admi- 
ralty 
Islander. 
A. 
110 
Oahu. 
D. 
110 
Hawaii. 
B. 
103 
New 
Zealand. 
Waikato. 
96 
Chat- 
ham 
Islander. 
A. 
106 
Queens- 
land, 
Aus- 
tralia. 
113 
Gipps 
Land, 
Aust. 
105 
Aus- 
tralia. 
104 
Basi-lambdoiJal. 
111 
123 
120 
130 
122 
112 
120 
115 
111 
110 
Perpendicular, 
129 
139 
147 
147 
146 
138 
144 
132 
126 
128 
Basi-coronal or bregmatie, 
130 
138 
144 
146 
143 
134 
144 
135 
124 
133 
Basi-glabellar, 
107 
111 
106 
113 
108 
110 
121 
108 
101 
114 
Basi -nasal, .... 
104 
106 
100 
107 
102 
104 
113 
97 
95 
102 
Basi-alveolar, .... 
99 
102 
98 
110 
100 
101 
106 
100 
94 
108 
From perpendicular radius to most 
anterior part of cranial cavity, 
89 
79 
82 
80 
87 
88 
92 
94 
83 
91 
From perpendicular radius to most 
posterior part of cranial cavity, 
75 
84 
87 
84 
74 
71 
76 
73 
82 
72 
perpendicular from the anterior end of this line at the basion, which intersects the cranial 
vault at a point behind the bregma. This point varies within certain limits in different 
skulls according to the inclination of the plane of the foramen magnum, for it is thrown 
backwards or forwards according as that plane diverges from or approaches the horizontal 
plane of the head. Speaking generally, it may be said to touch the cranial vault in 
more or less close proximity to the spot which corresponds to the upper end of the fissure 
of Rolando. 2 In the Admiralty Islander it was 18 mm., in the Oahuan 19, the Fuegian 22, 
the Chatham Islander 23, the Hawaian 31, the New Zealander 34, the Bush 37, one 
1 Proc. Boy. Soc. Edin., March 3, 1862. The drawings and tracings which I made at that time have not been 
published. 
2 See my papers On the Relations of the Convolutions to the Outer Surface of the Skull and Head, in Journ. 
Anat. and Phys., vol. viii. pp. 142 and 359 ; also Mr. Hare's paper in the same Journal, vol. xviii. p. 174. 
