338 N. AV. INGALLS 



seem to occur particularly when the lunate is far back as if similar 

 forces had caused a great transverse folding of the cortex. 



The region above the interparietal will not detain us. Brod- 

 mann ('07) states that it can be subdivided into anterior and pos- 

 terior halves, the line between the two being the superior parietal 

 or precuneal sulcus, this would harmonize with the findings of 

 Elhot Smith. 



The inferior parietal region shows in this brain, more clearly 

 on the right side, the three typical arcuate gyri, supramarginal, 

 angular and posterior parietal. Such an arrangement is by no 

 means the rule. This classical condition, with the addition of 

 sulcus intermedins primus, between areas 39 and 40 and in front 

 of the angular gyrus, and of the intermedins secundus within 

 area 39 behind the angular, is however schematic rather than 

 natural, and suggests a primitive condition. The furrows as they 

 stand in the chart are not calculated to allow for any great in- 

 crease in cortex and their number and relation is such that any 

 slight increase is apt to lead to a distortion of the primitive mark- 

 ings. Area 40, whose posterior limit is the sulcus intermedins 

 primus seems to be rather more constant than 39 behind it. This 

 latter area presents two furrows, lying wholly within it, the angu- 

 lar or the secondary termination of the parallel sulcus, and the 

 intermedins secundus, which is less constant. Whether or not 

 these furrows may be related to differences in the different parts 

 of the area, perhaps as yet potential, the future must decide. A 

 multitude of fissural combinations may occur here and any at- 

 tempted enumeration of them would, in the present state of our 

 knowledge, be wasted time. It is possible however, here as in 

 other regions to find the old landmarks, even although thay may 

 have forfeited entirely their original form, if strict attention be 

 paid to the grouping and to the characters of the individual sulci, 

 such as their depth and connections and the presence of annectant 

 gyri. But in addition to this the influence of neighboring parts 

 must be born in mind. 



By the identification of homologous sulci, as far as such an 

 identification is at present possible, we have mapped out homolo- 



