PHYHIOLOGICAL BBB1M, 



and rare condition of \\\<-, in.nular region. The sup -rior 

 limiting aloof fon both sides) passes forward and actually 

 joinH the fronto-orbital sulcus so as to r.owplctdy w,i\> out 

 HIM anterior insular n^ion. [til the Dorm.' M;ui. 



In the left liemi-|,h<-n- t.li<- superior and inferior pn;- 

 central sulci are confluent. 0. C. 1 



Presented by W. E. Leach, Esy. 



D. 668. The brain of a young female GTiimpanze- ' .!//// 

 ptiheeitS troglodytes). 



The left cerebral hemisphere has been separated. 



This is a small and in some respects simple brain. On 

 the right hemisphere the insular region present- tin- 

 simplest and most primitive Anthropoid type, i.e. the lips 

 of the superior limiting and the fronto-orbital sulci an- not 

 opercular and the sulci are widely separated. On the left 

 hemisphere, the sulci approach so close that they almost 

 meet (at a casual glance they appear to join) ; and there is 

 a faintly marked tendency to operculation. 



The extent of the occipital operculuin and the freedom 

 of the exposed surface of the occipital area from any other 

 sulci except the plain linear inferior occipital, are quite 

 Cercopithecoid characteristics. On the left hemisphere 

 the occipital operculuin has been cut away, and the wide 

 separation of the transverse occipital sulcus from the 

 bottom of the " Affenspalte " is thus demonstrated in a 

 much more decisive fashion than is the case in D. 664. 

 In this brain the parieto-occipital series is represented 

 by the parieto-occipital sulcus proper, a shallow sulcus 

 behind it, and especially by the deep mesial limb of the 

 transversal occipital sulcus. 



In front of the tortuous central sulcus there are typical 

 superior and inferior precentral sulci. The latter is fused 

 to the inferior frontal sulcus, which (in the right hemi- 

 sphere) gives off a peculiar mesial transverse branch. A 

 sulcus frontalis medius is (superficially) joined both to this 

 sulcus and also to the inferior precentral. 0. 0. 1338 I d. 



D. 669. The brain of a Chimpanzee (Anthropopithecus troglo- 

 dytes). 



This specimen is of interest as a demonstration of the 



