46 



SUPER-ORGANIC EVOLUTION 



these increase their force according as they establish 

 fresh connections. 



; 



FIG. 4. 



Progressive concentration of the sensitive cells in the animal series. A, 

 sensitive nerves of the lumbar ; B, sensitive cells of a mollusc ; C, 

 sensitive cells of a vertebrate. 



In fig. 5, taken from Ramon y Cajal, 1 the neuronas 

 have risen to a more elevated grade of organisation, 

 and we can easily understand the successive com- 



1 Texture of the Nervous System of Man and of the Vertebrates, 



