Chap. XIX.] DURING UTERINE LIFE. 345 



Lobe and the extent of the posterior prolongation of the 

 * fissure of Sylvius ' are also notable features of the foetal 

 brain. We have already had to refer to these charac- 

 teristics in the brains of many of the Quadrumana, and 

 we shall have occasion again to speak of the same pecu- 

 liarities as existing among fully developed Human Brains 

 of a low type. 



At the period of birth, with the fuller development of 

 the Parietal Lobe, the fissure of Rolando is much less 

 bent. The outline of the Brain seen from above is still 

 that of an elongated oval, though it is one which is dis- 

 tinctly fuller in the frontal as well as in the parietal region 

 than that of the seventh month foetus represented by 

 Gratiolet — the outline of which agrees almost exactly with 

 the outline of the brain of the adult Bushwoman given by 

 Marshall (fig. 135). 



According to S. Van der Kolk and Yrolik it appears 

 that in their relative proportions the lobes of the Brain in 

 a new-born Child, hold just the mean between those of a 

 Chimpanzee and of an adult Man. In the adult Orang, 

 however, the same proportion obtains between its different 

 lobes and those of the new-born Child — so that in this 

 respect, as in several others, the brain of the Orang seems 

 rather more highly evolved than that of the Chimpanzee. 



The Cerebellum in the new-born Child is comparatively 

 small. Its proportionate weight compared with that of 

 the Cerebrum at the same period, is lower than in either 

 of the great anthropoid Apes. This, however, is due not 

 to any diminution in the development of the Cerebellum, 

 but rather to the fact that in Man the amount of increase 

 in the size of the Cerebrum is much more considerable 

 than in that of the Cerebellum, and because this greater 

 increase is already, at the time of birth, more manifest in 

 the Cerebrum than in the Cerebellum. This fact waa 



