THE VITAL PROCESSES. 31 



life. Thus the adult butterfly is more highly organized 

 nervously than it was in the caterpillar stage. (Fig. 15.) 

 Similarly, the bees and the flies, with their fused ganglia in 

 the three regions of the body and the attendant centraliza- 

 tion of functions in those fused ganglia, are to be reckoned 

 as more highly organized living beings than are the locusts 

 with their much more nearly similar and segmentally 

 arranged ganglia. Examination of a series of animals 

 from the simple toward the complex shows one other fact 

 of nervous organization. The upward series shows a 

 tendency not only toward this fusion of ganglia and cen- 

 tralization of functions, but also to place the emphasis 

 upon the cephalic ganglion, centralizing in it the percep- 

 tion of stimuli which, lower in the series, were either dis- 

 tributed to other parts of the body for interpretation, or 

 were not differentiated from each other; as hearing, tast- 

 ing, and the contact sense. 



