40 Proceedings of the Royal Irish Academy. 



a marked example of a traction epiphysis. Frequently this trochanter is 

 associated with a fossa hypotroehanterica, the -whole arrangement being 

 indicative of a strong development of the gluteus maximus, and of a greater 

 attachment to hone than usual. 



The superior platymeria of these bones is perhaps the most interesting 

 feature in connexion with them. Both internal and external flanges were 

 seen, though not always on the same specimens. The dissociation of these 

 flanges would lead one to suppose either that they are due to different causes 

 or to the action of the same cause in different degrees. Since Manouvrier 1 

 published his paper it has been thought that the flattening is due to excess 

 development of the various constituent parts of the quadriceps, caused, he 

 believed, by the frequency of their contraction in a reverse manner to their 

 usual mode of action, the fixed point being distal. He pointed to the 

 occurrence of the condition among certain mountaineering races in whom the 

 movement of climbing would produce the above-described action of the 

 extensor mass. Platymeria, however, is neither invariable in races living in 

 mountainous districts, nor can it be limited to those races, as these bones 

 showed the condition well, corresponding to Hepburn's classification of 

 " distinct," the average index being 73 and the range 70-77. I have followed 

 Hepburn's method of measurement, and, to emphasize the prominence of the 

 feature, I would draw attention to the following figures, which are the 

 averages given by various authors for modern bones : — 



Modern British — Hepburn, 1 . . . 81-8. 



Modern French — Manouvrier," . . 882. 



Modern European — Scott.' . . . 86 - 6. 



Old Dublin, average of ten specimens, . 7 ; 3. 



The lateral extension appears to be always associated with a rough fossa 

 external to the gluteal line, apparently for insertion of fibres of the gluteus 

 maximus. The outer margin of the depression and the flange gives attach- 

 ment to the vastus lateralis, and the front of the flange affords origin to the 

 vastus intermedius. If this interpretation be correct, we must consider the 

 formation of the flange to be, in part, associated with increased attachment 

 of gluteus maximus pushing outwards the vastus lateralis, and in part due to 

 development of the vasti themselves. As has been remarked, the lateral 

 extension was more frequent than the medial, though it was, perhaps, best 



1 Manouvrier, Congres international d' Anthropologic et d'Archeologie prehistorique, 

 1889 ; Bulletin de la Societe d' Anthropologic de Paris, 1893, 1895. 

 - Hepburn, Journal of Anatomy and Physiology, 1897. 

 ' Manouvrier. Bulletin de la Societe d' Anthropologic de Paris, 1892. 

 4 Scott, Annals of Sew Zealand Institute, 1894. 



