126 
THE VOYAGE OF H.M.S. CHALLENGER. 
the frontal and occipital. Skulls which owe their dolichocephalic proportions to this 
dominating growth of the two parietal bones may appropriately be said to exhibit 
parietal dolichocephaly. The variations in the length of the arcs in the bones of the 
cranial vault will necessarily affect the cranial sutures, so that the coronal, squamous, and 
lambdoidal sutures will vary both in their direction and position within certain limits. 
As we have no evidence that the lobes of the brain grow commensurately with the bones 
of the cranium after which they are named, the relation which these lobes, and the fissures 
separating them from each other, will bear to the cranial sutures will also, as 1 1 and 
others have elsewhere pointed out, vary within certain limits, and these variations will 
render it difficult to lay down, from an inspection of the surface of the head, absolutely 
fixed rules for the determination of the position of the cerebral fissures and convolu- 
tions. 
Table XX. 
Cephalic Index, . 
Bush. 
Fue- 
gians. 
Austra- 
lians. 2 
Admir- 
alty Is- 
landers. 
Hawai- 
ans. 
Oahu- 
ans 
brachy- 
cephali. 
Oahu- 
ans 
dolicho- 
cephali. 
Oahu- 
ans 
mesati- 
cephali. 
Chat- 
ham Is- 
landers. 
New 
Zea- 
landers. 
New 
Guinea. 
South 
Sea Is- 
landers. 
1-5 
5- 
9- 
5'5 
2- 
5- 
3- 
4- 
8 - 
11- 
19-5 
9'6 
Vertical ,, 
4- 
3-5 
11- 
13- 
4‘ 
3- 
9‘ 
8' 
7- 
9’ 
7-5 
io- 
Gnathic ,, 
9-4 
3- 
16- 
18- 
7' 
5- 
14- 
11- 
8' 
11-5 
13- 
11- 
Facial ,, 
7 - 
14- 
17- 
14- 
6- 
7’ 
12- 
7- 
9-8 
21- 
13- 
12- 
Nasal ,, 
14-5 
8' 
14-5 
17’ 
11- 
12- 
11- 
io- 
12- 
20- 
io- 
4- 
Orbital , , 
Palato-maxillary Index, 
13- 
io- 
23- 
19- 
8- 
23'5 
16- 
9' 
15- 
20- 
18- 
30-5 
16- 
6‘ 
23-5 
17- 
io- 
19- 
27' 
15- 
13- 
22‘ 
32- 
21' 
The great importance which has been attached, in the later years of craniological 
research, to a determination of indices, by a comparison of two dimensions, leads me now 
to survey the several indices which I have computed in the preceding Tables, with the 
object of ascertaining which index shows the smallest range of variation in each series of 
skulls. For convenience of comparison I have arranged in groups in Table XX. the 
series of skulls examined, and the numerals express the range of variation in their several 
indices in the adults of each group. From this Table it will be seen that the cephalic 
and vertical indices showed the smallest amount of variation in each group. In the Bush 
skulls 1*5 expressed the range of the cephalic index, and in no group did it rise above 
10, except in such mixed people as the New Zealanders, where it reached 11, and the 
New Guinea skulls, which included both brachy cephalic and dolichocephalic races. The 
vertical index was remarkably constant in the Bush, Fuegians, Hawaians, and brachy- 
cephalic Oahuans, the range of variation not rising above 4. In the Australians the 
range was 11, owing to the presence of a proportion of dolichoplaty cephalic crania, and 
1 See Journ. Anat. and Phys., vol. viii. pp. 142 and 359. 
2 In estimating the range of variation of the cephalic index in the Australian skull, I have not included the 
scaphocephalic man from Portland Bay, or the mesaticephalic woman from West Victoria. 
