A Study of Cerebral Anthropology 35 



phology will take on a significance which has been hoped for, but 

 heretofore has not been realized. 



This is not the place to consider the long dispute which has been 

 carried on concerning this region in relation to the homologies 

 between man and apes. Although the work of Smith ( 1904) is 

 not accepted in all of its details by the various observers — (see 

 HoU (1907), Zuckerkandl ( 1904- 5-8-10) and Kohlbriigge 

 (1903)) — still the average hemisphere lends itself more readily 

 to his description than to any other ; consequently we will employ 

 his nomenclature. I may also add that the R.N. A. is entirely 

 inadequate for the description of this region in the light of our 

 present knowledge. 



Sulcus Lnnatiis: This sulcus which was named by Smith, and 

 which he considered the homologue of Riidinger's afifenspalte, is 

 the sulcus occipitalis lateralis of Eberstaller and the exoccipital 

 sulcus of Spitzka (1902;. After Cunningham (1892; proved 

 that the sulcus transversus (Ecker) was not the human represen- 

 tative of the afTenspalte of apes, he, with others, generally con- 

 sidered that the appearance of this ape fissure in the human brain 

 was of rare occurrence. This led to the report of cases of its 

 supposed presence on account of the general belief that such a 

 condition indicated marked atavistic tendencies. A review of 

 this literature was published by Pfister (1899). 



It is now known that the sulcus lunatus is present in the great 

 majority of human brains, either in the form of a lunate sulcus 

 defining the ' striate area,' or in the form of the sulcus lateralis 

 which is the lunate displaced (]\Iott, 1907). Every form of the 

 afifenspalte which is found in apes may also occur in the human 

 brain. It is rarely symmetrical on the two sides, and shape and 

 position may vary. The largest and most pithecoid forms are 

 generally found on the left side (Smith, 1904). Another varia- 

 tion is in the appearance of two segments representing the sulcus. 



The Sulcus Praclunatus: This is found extending forward a 

 variable distance from the sulcus lunatus, and when the latter is 

 broken up it may be found confluent with either segment. 



Sulcus Occipitalis Paramesialis: This sulcus may usually be 

 found on the dorsal surface of the occipital region, running 



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