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C. W. M. Povnter 



The Sulcus Front o-M arginalis : This sulcus has been known as 

 the fronto-marginal sulcus of Wernicke. It is situated, as its 

 name indicates, on the margin of the frontal lobe, and may be 

 represented by one, two or three segments. The normal condition 

 seems to be a division into two (Retzius 66 per cent.). Duck- 

 worth finds it is present and detached in the foetus in 78.6 per 

 cent. Elliot Smith (1902) considers this sulcus as a part of the 

 sulcus frontalis inferior. Duckworth (1907) considers the sulcus 

 as two terminal portions and a stem ; this he finds recognizable in 

 71.4 per cent, of Australians. He does not agree with Cunning- 

 ham that the lateral branch is developmentally the older of the two 

 terminal portions. 



Sulci Orbitales: These sulci have been exhaustively studied by 

 Eberstaller and a very complex classification suggested. I do not 

 think that any morphological significance attaches to them, con- 

 sequently the division into simple and complex arrangement wall 

 adequately express the condition. 



The four-convolution type of the frontal lobe was first spoken 

 of by Benedikt who saw in the condition a similarity to the ar- 

 rangement in some of the lower mammals and concluded that the 

 principle can be clearly established that delinquents constitute one 

 variety, and a retrogressive variety, of the genus homo ; for he 

 did not believe that the condition obtained in the brains of non- 

 criminals. He also found two cases among criminals, of a five- 

 convolution type. Hanot agreed in general with the idea ex- 

 pressed by Benedikt. Later study has shown that Benedikt's 

 idea was without proper foundation ; for Giacomini found that 

 the four-convolution type js present in 13.5 per cent, of normal 

 brains, and Sernoff found it present in 14.5 per cent, of his series. 



REGIO PARIETO-OCCIPITALIS. — LATERAL SURFACE 



Sulcus inter parietalis: (B.N.A.) The sulcus interparietalis has 

 been studied by a great many observers, each using his own 

 interpretation. Its morphological significance and normal arrange- 

 ment are, possibly, still a matter of question. It was first named 

 by Turner (1866). It is present in the sixth month of foetal 

 life, and is common to both man and apes (Ecker). I will not 



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