20 
HORN EXPEDITION—ANTHROPOLOGY. 
The left tibia of this Central Australian native is represented in the accom¬ 
panying Plate, and sections are also shown of the same bone at its mid-point 
and at the point of junction of the upper and middle thirds. These may be 
compared with corresponding sections of a normal European tibia and of two 
of the most platycnemic tibiae I possess. It is remarkable that these latter 
sections, differing so conspicuously from one another, are from bones of natives 
belonging to the same locality and tribe. Indeed, an examination of the form 
of a number of Australian tibia3 shows a remarkable degree of variation in the 
sections. The comparison will show that, though the curvature is considerable in 
the McDonnell Range tibia, the platycnemia is not nearly so well-marked as in 
the bones of the two other South Australian natives. 
I may say, in reference to the explanation that platycnemia may be a modifi¬ 
cation of form due to the increased area for the origin of the tibialis posticus 
muscle, which is connected with the freedom of movement and extent of use of the 
muscles of the leg that might be expected to reach a maximum of development in 
races living in mountainous or rugged country, or in those whose existence entails 
the necessity of following the avocation of hunters, that all the skeletons examined 
by me, in which platycnemia was often extremely well-marked were, with the 
exception of the Alice Springs skeleton, those of natives of the plains, or, at all 
events, of country that could not in any sense be called mountainous.* Still the 
principle of the explanation is well worth consideration, for the Australian native 
is well known to be perpetually on the tramp, either in pursuit of game or in the 
course of his wandering life. 
In conjunction with my colleague. Dr. Watson, Professor of Anatomy, to 
whose experience I appealed, I have examined a considerable number of Australian 
tibise, nearly all of them more or less platycnemic, and I find that though the area 
of the surface of origin of the tibialis posticus is undoubtedly increased in many, 
in others this is certainly not the case. In this connection of alleged increased 
muscular activity it may be worth mentioning that Professor Watson, while having 
no record of abnormalites in the tibialis posticus muscle itself, found in one 
aboriginal subject a very large flexor accessorius. The outer or tendinous head 
was wanting, but the inner (muscular) head was immense, and it ran into the 
flexor longus hallucis (a very strong muscle), instead of into the flexor longus 
digitorum. 
“Manouvrier. Sur le platycnemie, etc. Mem. Soc. d’Aiithrop., Paris, 1888. I rejfret that I have not been able 
to refer to this paper, and I am indebted for a short epitome of the author’s conclusions to a paper on the 
“ Influence of posture on the form of articular surfaces of the tibia and astrag-alus,” by A. Thomson. Journal 
Anat. and Phys., Vols. XXHI. and XXIV. 
