70 
Proceedings of the Royal Society of Edinburgh. [Sess. 
IV. — On a Numerical Determination of the Relative Positions of 
certain Biological Types in the Evolutionary Scale, and of 
the Relative Values of various Cranial Measurements and 
Indices as Criteria. By K. Stuart Cross, M.Sc. Melb. (From 
the Anatomy Department of the University of Melbourne.) Com- 
municated by Professor R. J. A. Berry. 
(Read March 7, 1910. MS. received July 5, 1910.) 
The present investigation arose in part as an examination into, and an 
extension of, an attempt by Professor R. J. A. Berry and Dr A. W. D. 
Robertson * at placing the Tasmanian aboriginal in his relation to various 
other racial types, extinct and existent. It has resolved itself into a 
numerical calculation of the approximate relative positions of these types 
in the evolutionary scale, together with a determination of the relative 
values of various cranial measurements and indices employed by Schwalbe 
in his “ form analysis ” of the calvarium, as criteria is assigning these 
positions. 
I am also indebted to the above authors for the collected data on which 
the present work is based. These data are set forth in Table I. For an 
account of the various sources and authorities for the figures there given, 
reference may be made to the above-mentioned paper. The order of the 
various titles of measurements and indices in this table is purely one of con- 
venience, being determined by the absence of various measurements for one 
or other type of cranium, except that the last three occupy their positions 
at the foot of the list because of their non-inclusion in the subsequent 
calculations. 
Of the various measurements under consideration, the great majority 
show a general increase or decrease in passing from the anthropoid ape to 
modern man. Those of the glabella-inion length and the length of the pars 
glabellaris of the os frontale do not, however, satisfy this condition. They 
appear to rise irregularly to a maximum and then to recede. As this 
investigation is based on the assumption that the increase or decrease, 
where continuous throughout the scale, is proportional to the increase in 
the degree of development, these two measurements have been rejected. The 
relative weights they would have carried had they been included have, 
* Berry and Robertson, “ The Place in Nature of the Tasmanian Aboriginal as deduced 
from a Study of his Calvarium,” Proceedings of the Royal Society of Edinburgh, 1910, vol. xxxi. 
