492 THE HIGHER ANTHROPOIDS 



Measurements a\d Txdtces of the Oraxg-Oitang 



The cranial nicasLUfiiU'iits ol tlic orang-outang arc: 



Occipito-nasal diameter 165 mm. 



Intertemporal width 88 mm. 



Breadth of brain case 98 mm. 



The dimensions ol the ijram, inchidmg cercbelhim and brain stem, are: 



Longitudinal 96 mm. 



Transverse . 84 mm. 



The l)ram is markedly gyrencephalic \\ ith its lissural pattern eor- 

 rcspondmg closely m detail to that ol the human brain. 



Total weight of the I)rain 246 gm. 



Total water displacement ol the brain 250 e.c. 



Weight ol the lorebram 213 gm. 



W eight ol the midbrain 4 gm. 



\\ i-ight ol the hmdbrain iq gm. 



The water displacement ol the sexeral portions ol the brain gave the 

 following results: 



\\'ater displacement ol the forebrain 2 h) e.c. 



\\ ater dis]>lacemcnt ol the midbrain 3 e.c. 



\\ ater displacenu'iit of the hmdbrain 28 e.c 



On the basis ol these ligures, the lollowmg encephalic indices were 

 computed: 



Forebrain index 83 per cent 



Midbrain index 5 per cent 



Hindbrain index 12 per cent 



