8-2 MAN 



TIIF. FRONTAL LOBE OF PITHECANTH KOPUS ERECTUS 



The troiital lobe appears as a part leularly eonspieuous portion ol tlie 

 hemisphere (Fig. 366). It is promiin'iit especially because of its large size and 

 pronounced comolut ions. Near the middle ol the frontal eoincxity and in 

 ju\taj)osition with the superior longitudinal hssure is a prominent Pacchion- 

 ian enlargement. 1 he relief of the frontal coiuolutions is especially note- 

 worthy as it gives this region of the brain an indi\ idualit\ possessed by no 

 other area. This observation does not impl\ that the eonvohitional process 

 is suprt'me m the Irontal lobe of pithecanthropus. It demonstrates, as 

 Schwa I be has pre\i()usl\' shown, that the frontal sc|uam()sa is more impression- 

 able to brain growth than other parts ol the skull, it is fortunate, moreo\'er, 

 that such IS the case, for it is this region of the hemisphere w Inch has most to 

 reveal regarding the higher psychic development ol the brain. Nor should it 

 be overlooked that this Irontal lobe represents the latest accessions of 

 human specialization, w lu'reb\' man has distinguished himself in cremation and 

 finally acquired all that is implied in the titli', "Ilomo sapiens." 



There is a slight asymmetry m the size and shape of" the frontal lobes, 

 the left being somewhat larger. This also applies to the frontal comolut ions 

 of the k'lt side. In ri'lati\e size tlu' Irontal area represents upon its latt'ial 

 surface more than oiu'-third of the entire e\|)osed convexity of the hemi- 

 sphere. The two frontal lobes togetluT, w luai \ k\\ x'd from aboxc, giNc the 

 impression ol a t nincated p\ ramid. There is a marked bluntness at the frontal 

 pole and the outlines extend backward with a gradual widening to the level 

 of the Rolandic lissure. This general broadtaimg is not consistentl\ main- 

 tained. In OIK' zone there appears to be a eonsideral)le constriction, hor 

 purposes of subsec|ueiit identification this zone is calk'tl \\)v coronal conslric- 

 tion. It begins at either Irontott'iiiporal notch and follows tlu' impression 

 of the coronal suture to the midline. 



