414 J. J. KEEGAN 



comparison, but it is not unreasonable to expect that a closer 

 clinical or functional analysis may disclose more features that 

 can be translated as indications of the predominance of functions 

 upon one side or the other of the brain. An interesting observa- 

 tion would be to determine if a predominant vision with the 

 right eye is related to a more prominent area striata and sulcus 

 Kmatus of the left hemisphere. 



The most striking differences between the two hemispheres of 

 this brain are found in the occipital, parietal and central regions. 

 The sulcus lunatus can be identified only in the left hemisphere 

 where it is very prominent and associated with a more lateral 

 extent of the area striata, a larger, more lateral and more inde- 

 pendent sulcus occipitalis triradiatus, a sulcus occipitalis para- 

 mesialis more upon the lateral surface, a sulcus occipitalis in- 

 ferior nearer the lateral surface and in arcuate communication 

 with the sulcus occipitalis anterior. 



The inferior parietal area is more extensive in the right hemi- 

 sphere and the increased growth appears to be in the anterior 

 portion. This is evidenced by the extension of the anterior ex- 

 tremity of the sulcus interparietalis into this region and the 

 more posteriorly situated sulcus angularis. The conformation 

 of the sulcus iriterparietalis of the left hemisphere would seem 

 to indicate a predominance of growth in the superior parietal 

 lobule. This has resulted in a low position of the sulcus inter- 

 parietalis, a posterior deflection of the sulcus post-centrahs and 

 a striking anterior arching of the sulcus centralis above its su- 

 perior genu. The lower part of the gyrus post-centralis is also 

 widened by the posterior deflection of the inferior extremity of 

 the sulcus post-centralis. The entire gyrus is noticeably wider 

 than in the right hemisphere. 



The value of these observations of the dissimilarity of the two 

 hemispheres is difficult to judge on account of the lack of knowl- 

 edge of the extent of unilateral functional predominance and of 

 clinical tests to corroborate the morphological findings. The 

 study is interesting from an anthropological standpoint, dem- 

 onstrating that in a race of inferior status all of the elements 

 necessary for a higher individual development are present. 

 The same condition was concluded in the Negro brain (Poynter 



