64 Proceedings of the Royal Society of Edinburgh. [Sess. 
tion,” is open to the objection that the spacing between the compared 
objects is always the same, namely, unity, and that it does not therefore 
sufficiently allow for marked morphological intervals, we submitted the 
method to a mathematician, Mr K. S. Cross, M.Sc., who points out that 
mathematically the “ unit interval system of classification affords nothing 
more than a rough approximation of the relative evolutionary positions of 
the compared objects, because it simply allots to them successive numerical 
integral values from unity onwards.” He has therefore been good enough 
to deal with the whole question from a mathematical standpoint in his own 
paper, which follows, and to which the reader is referred. 
Whilst we claim neither infallibility nor finality for these particular 
applications of biometric methods to scientific results, as suggested by us, 
and subsequently worked out by Mr Cross, and notwithstanding that there 
are at first sight one or two apparent singular anomalies, the final results 
as set forth in fig. 1 of Mr Cross’s paper must inevitably afford much 
ground for thought and reflection. 
In the first place, it can be no mere coincidence that our methods place 
primitive man in almost precisely the same order as given by Schwalbe in 
his “ Das Schadelfragment von Briix und verwandte Schadelformen.” This 
is so striking that we cannot do better than place the two results side by 
side, as follows: — 
Schwalbe. 
Berry, Robertson, and Cross. 
(See Cross’s paper.) 
Neanderthal ] 
| 
Spy , 
> Homo primigenius. 
Spy- Neanderthal . 
Krapina 
) 
Gibraltar. 
Gibraltar. 
Abstand. 
Briix 1 
1 Homo fossilis, variety of 
Briix. 
Galley Hill J 
1 Homo sapiens. 
Galley Hill. 
Briinn. 
Tasmanian. 
Anstralneger. 
Briinn. 
Rezenter Mensch. 
European. 
Not only is the order almost precisely the same in both instances, but 
in the exact place where Schwalbe hypothecates an interval, that is, between 
the Gibraltar and Briix remains, so also does Mr Cross’s figure actually 
demonstrate such an interval. 
The position of Pithecanthropus erectus is, in view of the difference of 
opinion which exists as to the human, transitional, or apelike character of 
