134 Proceedings of the Royal Society of Edinburgh. [Sess. 
arc in the Neanderthal skull does actually owe its origin to physiological 
factors through which environment acts, the status of that type of skull 
in the evolutionary sequence will be materially affected. . . . The 
Gibraltar skull is flattened owing to its low place in evolution. But as 
regards the flatness of the brain case (called the platycephalic character) 
of the Neanderthal calvaria and its congeners (as contrasted with the 
Gibraltar specimen) Dr Sera suggests dependence upon the particular 
environment created by glacial conditions.” 
It is thus obvious that the degree of flattening or otherwise is, in view 
of modern opinion, an important present-day field of research, and its 
estimation for the Tasmanian is the chief object of the present work. The 
investigation of the problem is, however, very considerably handicapped 
by the fact that Sera’s original paper is not available in Melbourne, in 
either its original form or in any adequate abstract. With this important 
reservation, I have estimated the degree of curvature, or flattening of the 
glabello-bregmatic arc of the frontal, total parietal arc, and superior 
occipital arc of the os occipitale by Klaatsch’s “index of curvature,” all 
the observations having been made upon the median sagittal plane of the 
Tasmanian life-size tracings already referred to. For a diagrammatic 
explanation of the observations thus recorded, the reader is referred 
to fig. 1. 
The following twelve observations have thus been recorded : — 
Os Frontale. 
1. The length of the glabella-bregma arc. 
2. The length of the glabella-bregma chord. 
3. The length of the greatest distance of the arc from the chord. 
4. The index of frontal curvature (Klaatsch). 
Os Parietale. 
5. The length of the bregma-lambda or parietal arc. 
6. The length of the bregma-lambda or parietal chord. 
7. The length of the greatest distance of the arc from the chord. 
8. The index of parietal curvature (Klaatsch). 
Os Occipitale. 
9. The length of the lambda-inion or superior occipital arc. 
10. The length of the lambda-inion or superior occipital chord. 
11. The length of the greatest distance of the arc from the chord. 
12. The index of occipital curvature (Klaatsch). 
The individual measurements of each of the above, together with 
minimum, average, and maximum results for the whole series of fifty-two 
Tasmanian crania, are set forth in Table II., which is uniform throughout 
