A Study of Cerebral Anthropology 59 



insula. This is not the result of hardening, for the condition was 

 noticed when the brain was first removed. 



The anterior and horizontal rami of the fissura Sylvii are well 

 separated and cut the dorsal operculum deeply. The ramus as- 

 cendens posterior is characterized by its extreme brevity. It ter- 

 minates by bifurcation. There is no distinct ramus posterior 

 descendens. 



Sulcus centralis is separated from the fissura Sylvii by a broad 

 gyrus, it terminates superiorly at the mesial border of the hemi- 

 sphere ; there are no anastomoses established with other fissures 

 although the anterior and posterior central gyri are cut deeply by 

 short fissures from both the central and prae- and retro-central 

 sulci. Submerged interlocking gyri mark the junction of the 

 middle and upper thirds of the fissure. 



Frontal Region 



The development of the convolutions of this region, as noted 

 above for the dorsal operculum, is not of high order. 



The sulcus praecentralis inferior is short and presents very com- 

 plicated connections ; it is confluent below with the fissura Sylvii 

 through the sulcus diagonalis. The sulcus terminates in the ramus 

 horizontalis and through this ramus communication is established 

 with the sulcus praecentralis superior. Sulcus praecentralis supe- 

 rior is almost divided into two segments by an annectant, it ter- 

 minates some distance from the mesial border and in this space is 

 a well developed sulcus praecentralis marginalis. 



The gyrus frontalis superior is indented by four short furrows 

 which represent the sulcus frontalis mesialis. Sulcus frontalis 

 superior is a continuous very tortuous sulcus which reaches nearly 

 to the frontal extremity of the hemisphere. It is confluent with 

 the sulcus praecentralis superior and with a segment of the sulcus 

 fronto-marginalis. If the sulcus frontalis medialis is present, it is 

 only as a short segment connected with the superior frontal, or as 

 a part of the complex connected with the inferior praecentral. 

 The sulcus frontalis inferior is without connections and an annec- 

 tant just below the surface divides it into two almost equal seg- 

 ments. The sulcus radiatus (E) is just below and parallel to it. 



403 



