Explanation of Plates. 
Of the plates wliich follow, Nos. IX. to XIX. inclusive are reproductions 
from photographs taken by Professor Spencer and Mr. Gillen, as ijidicated in 
each case. 
PLATE I. 
Fig. 1. Left tibia of skeleton from Alice Spring.s, showing slight degree of 
Camptocncmia. Length 17^ inches. Platycnemic Index 73-7. 
Fig. 2. Sections of the same tibia, the left being that taken at the junction of 
the upper and middle thirds and the right at the mid-point of the 
bone. 
Fig. 3. Corresponding sections of normal European Tibia. Length 14] indies. 
Fig. 4. Corresponding sections of Platycnemic Tibia of an Australian aboriginal 
from the South-east of South Australia. Length 15|^ inches. 
Platycnemic Index 69‘4. 
Fig. 5. Corresponding sections of Platycnemic Tibia of an Australian aboriginal 
from the same locality as the preceding. Length 141 inches. 
Platycnemic Index 57‘9. In each case ex and in indicate the 
anatomical external and internal borders. For further particulars 
on Platycnemia and Camptocnemia vide pp. 19-22 of text. The 
Platycnemic Indices are derived from measurements taken at the 
level of the nutrient foramen, so as to be comparable with those of 
other observers by the formula trans. diameter a; lOO = Platyc¬ 
nemic Index ant. post, diameter ; but in view of the variation of 
the nutrient foramen, I can see no reason why the mid-point 
should not be that selected. 
25a 
