64 SUPER-OKGANIC EVOLUTION 



The corpuscule marked by the letter a shows a 



FIG. 13. 



Young pyramidal cells of the cerebral cortex of a human embryo 23 centi- 

 metres long, a, cells without basilar edges ; &, cell in which these 

 little teeth begin to evolve; c, cell in which these basilar edges are 

 fairly developed. (After A. Kolliker.} 



shoot and protoplasmic peripheric ramifications 

 slightly developed, ^but without collateral little teeth 



