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finds it difficult to believe that such a sharp-edged, deeply-grooved 

 sulcus can be produced by what he describes as the weak fibres of 

 this portion of the sacro-iliac ligament. It is true that the "iliac" 

 part of the ventral ligament is comparatively thin and weak and is in 

 fact barely more than a strengthening of the capsule of the joint; but 

 the longitudinal fibres as described in the above dissection, are of 

 great thickness and strength, and supply the "accidental" case which 

 Prof. ViRCHOW hoped would arise to explain the development of this 

 interesting sulcus. 



If the explanation of the presence of the sulcus, given in this 

 paper, be true, then it is not difficult to understand that the groove 

 may be of unequal development on the opposite sides of the same 

 pelvis. For inequality in length of the lower limbs, or greater fixation 

 of the ilium to the sacrum on one side, would easily explain the greater 

 or less accentuation of this groove. In a case of congenital fusion of 

 the sacrum and ilium on one side, met with by the writer, the prae- 

 auricular sulcus was absent altogether on the fused side, and only 

 very faintly marked on the free side. In this case parturition was 

 impossible, and the head of a full-time foetus was found firmly fixed 

 in the pelvic cavity. 



In point of fact however it is uncommon in the writer's experience, 

 to find much difference in the development of the groove on opposite 

 sides of the same pelvis. On the other hand the groove may be absent 

 in females, either because the bones are still young, or because the 

 shape of the ilium and the amount of its fixation to the sacrum, are 

 in excess of the normal female arrangement and simulate the condition 

 in males. 



It has been said that the sulcus is not so well-developed in 

 modern European bones as in those of ancient and more primitive 

 races. The case described by Prof. Viechow is an example of what 

 may be found in the dissecting room today, and the photograph shown 

 in Fig. 1 of this paper illustrates the condition of the groove in a 

 woman found in the plague pits of Whitechapel of seventeenth century 

 date. This is one of a large number of hip bones from the same 

 place, which the writer has had the opportunity of examining through 

 the kindness of Prof. Thane. 



