250 



THE GROWTH OF THE BKAjx. 



segment of the central system. It was an easy inference 



from this arrangement 

 % 3 ^ .y tnat tne portions of the 

 -'1 ^ 2 central system with 

 which a segmental pair 

 of nerves was con- 

 nected, was also the 

 portion in which oc- 

 curred the principal 

 central adjustments 

 concerned with this 

 pair, but the question 

 remained as to the 

 significance of those 

 portions of the central 

 system which are more 

 elaborated and are 

 not so plainly seg- 

 mental. It is naturally 

 asked whether these 

 parts, such as the cere- 

 bellum, for instance, 

 are exclusively asso- 

 ciated with the nerves 

 which join the axis in 

 their immediate neigh- 

 bourhood, or whether 

 they have wider and 

 more general connec- 

 tions. 



We have seen reason 

 to think when examin- 

 ing the phylogenetic 

 modifications which the mammalian nervous system 

 has undergone, that there is a strong tendency to break 



ilii. 



