398 



THE EXTERNAL CONFIGURATION 



Hemisphere, instead of being much less, is about equal to, 

 or it may be of even slightly greater bulk than, the con- 

 joined Fronto- Parietal segment. Thus the proportions 

 met with in the lower human types are, as it were, in- 

 termediate between those 

 which obtain in the higher 

 human types on the one 

 hand and in the Quadru- 

 mana on the other. 



The diminution in size 

 of the Temporo- Occipital 

 segment in the brain of 

 human beings generally, is 

 perhaps more apparent than 

 real. The very great in- 

 crease in the size of the 

 Frontal and of the Parietal 

 regions is, at least in part, 

 another means of accounting 

 for the altered proportion. 



FIG. 145.-Under Surface of Cerebral It is Certain, indeed, that 

 Peduncle, Pens, and Medulla, showing ^ Q convolutions of the Tem- 

 Connections of the Cranial Nerves. (Sap- 



pey, after Hirschfeid.) poral Lobes tend to become 



1, Infundibulum of pituitary body; complex in higher 



2, part of floor of third ventricle ; 3, cor- 

 pora mamillaria; 4. cerebral peduncles; human brains, and it is 



5, pons ; 6, optic nerves, crossing in the .., . , , 



middle line so as to form the chiasma ; equally Certain that there 



7, common motor nerves of eyeball; j g a } go a tendency to ai 



8, nervus patheticus; 9, trigeminus ; . ^ 



10, external ocular nerve; 11, facial nerve; actual increase in til 6 S1Z( 

 12, auditory nerve ; 13, nerve of Wrisberg ; /? ,1 fWl'rntfll Lnhpq 



14, glossopharyngeal nerve; 15, vagus or 6S ' 



pneumogastric ; 16, spinal accessory ; the niOl'6 highly 6VOlveC 



17, hypoglossal nerve (cut away on one , 



3ide ) brains these Lobes become 



deeper and also fuller an< 



more rounded. There is, moreover, a notable increase ii 

 the complexity of the Occipital Convolutions. 



