76 THE KEILOR FOSSIL SKULL: PALATE AND UPPER DENTAL ARCH 
From these measurements it will be seen that the Keilor is larger 
than average Australian and Tasmanian skulls, but with the two 
exceptions of Gz (the inner width of the palate between the 2nd 
molar teeth) and ¢.c., all measurements of the Keilor skull lie 
within those of the largest recorded Australian skulls. Seven of 
its measurements exceed the maxima of those recorded by the 
writer for Tasmanian skulls. 
The Keilor skull with a Gnathic Index of 99:1 and the average 
Tasmanian skull with a Gnathic Index of 101°4 are mesognathic; 
the average Australian skull has a Gnathic Index of 104°5 and is 
prognathous. 
The palate of the Keilor skull is very large and well developed. 
Though larger measurements are recorded by Campbell for some 
Australian skulls, the upper jaw of the Keilor skull is larger than 
most modern Australian jaws and is larger in a number of its 
measurements than any of the Tasmanian jaws examined by the 
writer. 
The teeth of the Keilor skull, though slightly smaller in their 
mesio-distal diameters than the average corresponding Australian 
and ‘Tasmanian teeth, are about the same size in bueco-lingual 
diameter ; all measurements fall within the range of measurements 
for corresponding Australian and Tasmanian teeth. 
The teeth are too much worn to admit a comparison of cusp 
form, but the type of wear is similar to that found in Australian 
and Tasmanian cusps. The food of Keilor man was evidently 
coarse and required vigorous mastication. 
Any supernumerary tooth such as the one situated in the hori- 
zontal part of the left maxilla of the Keilor skull is rare in primi- 
tive skulls. No similar occurrence is recorded by Campbell in the 
series of 630 Australian skulls examined by him nor by the writer 
in Tasmanian skulls. Since radiographs were unsuccessful, it is 
impossible to determine its form without dissecting out the tooth. 
A comparison of the Keilor palate with those of Tasmanians 
and Australians (Pl. VII and VIII) discloses that it is more 
Tasmanoid than Australoid in the following respects: 
1. The palatal contour is horseshoe-shaped, with the third 
molars turning well inwards. 
2. It is relatively broad like the Tasmanian palate (brachy- 
uranic) ; the Australian palate is relatively narrower (doli- 
churanic). 
3. Well-developed maxillary and palatine tori are present. 
4, The infra-orbital fossa is deep. 
To Mr. L. A. Baillét of the Melbourne Technical College I am 
