A Study of Cerebral Anthropology 53 



and ramus horizontalis are present and widely separated ; the lat- 

 ter has connected with it the sulcus diagonalis (Eberstaller), the 

 connection being marked by a deep annectant gyrus. The ramus 

 posterior terminates in one limb instead of branching and without 

 any anastomosis. The very superficial furrow which occupies the 

 position of the ramus posterior descendens is undoubtedly the 

 representative of that furrow. 



Sulcus centralis. — This sulcus is without interest. It is sepa- 

 rated from the fissura Sylvii by a well developed gyrus, estab- 

 lishes no connections with the furrows on either side of it, and 

 terminates by a sharp bend backward of its single limb well 

 beyond the mesial border of the hemisphere. The gyri prae- 

 centralis and retrocentralis are regular in contour and well 

 developed. 



Frontal Region 



All of the convolutions of this region appear to be very fully 

 developed and regular in arrangement ; the three-convolution type 

 is present. 



Sulcus praecentralis inferior is parallel to the sulcus centralis. 

 It is confluent below with the fissura Sylvii by a deep furrow ; 

 at about the point where the ramus horizontalis should be, there 

 is a furrow thrown diagonally across thecourse of this sulcus prae- 

 centralis inferior which probably is the representative of that sul- 

 cus, although there is no deep annectant to confirm the opinion and 

 the sulcus continues upward without interruption or change of 

 depth into the sulcus praecentralis superior. 



The sulcus praecentralis superior continues upward almost to 

 the mesial border of the hemisphere. It sends a shallow branch 

 back into the gyrus praecentralis, and anteriorly there is a shallow 

 groove which communicates with the sulcus frontalis superior. 



The sulcus frontalis mesialis is represented by four short sepa- 

 rate segments that appear as simple indentations on the broad 

 superior frontal convolution. 



The sulcus frontalis superior is in the form of one continuous 

 fissure which extends well over the frontal pole of the hemisphere. 

 A bridging convolution, sunk just below the surface, divides it 

 into two segments of which the posterior is the deeper and longer. 



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