15 



fluence, and that lifting heavy weights may play an important role 

 in its production. With regard to the presence of a pronounced 

 sulcus in poorly-developed bones, particularly in those of women, 

 Zaauer makes the important suggestion that perhaps numerous past 

 pregnancies may not have been without effect. 



The object of this paper as the title implies is to supply evidence 

 which will satisfactorily account for the observed phenomena. 



In the year 1907 while the present writer was working in the 



Fig. 2. Left hip bone of a predynastic Egyptian woman. The sulcus praeauri- 

 «ularis is very well-developed, and the ilio-sciatic notch is very shallow and wide. 



Government Medical School at Cairo, on the skeletons of predynastic 

 Egyptians, his attention was attracted to the sulcus by its frequency 

 and extraordinary proportions in many pelves (Fig. 2). He was at 

 that time engaged in sexing the large series of hip bones which form 

 part of the collection, and it was not long before it became evident, 

 that though the sulcus was present in a more or less well-developed 

 form in a large number of the bones, yet that it was invariably in 

 the female that it reached its greatest and most striking dimensions. 

 Further careful examination of the hip bones showed that the sulcus 

 was frequently absent in males, and that when present, it was very 

 slightly developed being both narrower and more shallow than is the 

 case in women (Fig. 3). 



