42 
THE VOYAGE OF H.M.S. CHALLENGER. 
alveolar diameters, is not a necessary condition of the Australian skull. Prof. Flower 
places (New Cat.) the gnathic index of fifty-one specimens at 103 '6 which brings them just 
within the prognathic division, but in his "Native Races" he states that there is con- 
siderable individual variation in these crania, as in five out of forty-two specimens the 
basi-alveolar diameter was less than the basi-nasal, and in seven specimens these two 
diameters were equal. The range of individual variation in my series of crania was from 
92 in a female to 108 in a male skull, and the mean gnathic index was not so great as in 
the College of Surgeons specimens, so that the average was mesognathic. In the College 
of Surgeons series this index in the females was nearly 105, and more than in the males, 
where it was 103 ; but in my series the male average of 100 '6 was greater than the 
female average of 99*7. 
The mean nasal index obtained by MM. de Quatrefages and Hamy, by Prof. Flower, 
and by myself, places the Australian skull in the platyrhine division, but whilst the 
average of thirty-one skulls measured by the first named was 5 7 '9, and that of Prof. 
Flower was 5 6 '9, my average was considerably lower, only 5 3 "5. Of the twenty-nine 
specimens which I measured, sixteen were platyrhine, twelve were mesorhine, and one 
was leptorhine. The presence of a leptorhine nose amongst the Australians is so rare 
that the authenticity of any specimen possessing this character requires to be well 
established. Of the authenticity of the skull of the Muclgee tribe, with its nasal index 
only 46, there can be no question. The circumstances under which it was got are 
related in the note p. 29, and, moreover, it was one of the skulls from which an incisor 
tooth had been extracted at puberty. The anterior nares in this specimen were not only 
narrow in relation to the height, but their absolute width was only 22 mm. The skull 
of a Hobson's Bay native had also a nasal index of only 48, one from Gipps Land 49, 
specimens from Perth and Portland Bay of not more than 50, Eoebuck Bay 51 l , and 
all these were genuine Australian crania. Hence individual crania may possess a much 
lower nasal index than has usually been ascribed to the skulls of this race. 
The mean orbital index of thirty-one skulls in MM. de Quatrefages and Hamy's table 
is 78'81, that obtained by Prof. Flower from fifty-one skulls is 80'9. These observers, 
therefore, have placed the Australian skull in the microseme series, which corresponds 
with my measurements of the male skulls ; but owing to the megaseme proportions of so 
large a number of my female skulls, my average of the whole is raised to 84, which 
brings them just within the mesoseme series. In MM. de Quatrefages and Hamy's table, 
as well as in my own, the female index is considerably higher than the male, more so 
indeed than seems to have been obtained by Prof. Flower in his measurements, who in 
his " Native Races" places the male orbital index at 81 "8, and the female at 82'9. 
1 Although the Roehuck Bay skull has a nasal index of only 51, i.e., was mesorhine, yet the width of the anterior 
nares 28 mm., was only 1 mm. less than the widest of all the crania measured. Its diminished index was therefore due 
to the height of the nose 55 mm., which, with one exception, reached its maximum amongst the Australians in this 
specimen. 
