498 C. M. Child. 



But the primary object in introducing this case was to show how 

 completely these organs can regenerate in the absence of the gan- 

 glia. So far as can be seen they are as perfect as in pieces con- 

 taining the ganglia. 



The conclusions reached from these experiments may be 

 summed up as follows: the influence of the cephalic ganglia upon 

 posterior regeneration is not "formative" for the same organs 

 are regenerated whether the ganglia are present or absent. The 

 amount of regeneration and the size and extent of various organs 

 are, however, greater in the presence of the ganglia. This 

 quantitative diff^erence is probably due to the fact that all func- 

 tional stimuli and conditions connected with muscular activity 

 and especially those connected with the coordinated muscular 

 activity of locomotion occur with much greater frequency and 

 intensity when the ganglia are present. Probably other func- 

 tional conditions whose existence is less easily determined are also 

 present in greater degree when the ganglia are present. 



c. Posterior Regeneration in the Absence of the Cephalic Gan- 

 glia and Parts of the Longitudinal Nerve Cords. 



The object of these experiments was to compare the posterior 

 regeneration at a given level in pieces with anterior ends at different 

 levels posterior to the ganglia, in order to determine whether the 

 removal of a considerable part of the nerve cords in addition to 

 the ganglia had any effect on regeneration. In the section on the 

 nervous system and behavior mention was made of the fact that 

 pieces from the posterior region of the body show less motor 

 activity than pieces of the same size from the anterior regions, 

 posterior to the cephalic ganglia. These facts would seem to 

 indicate that the anterior regions of the longitudinal nerve cords i 

 differ in some respect — perhaps in complexity — from the posterior 

 regions. 



In order to test still further the hypothesis of the relation 

 between posterior regeneration and motor activity pieces with 

 posterior ends at the same level of the body and anterior ends at 

 different levels posterior to the ganglia were used. Certain diffi- 

 culties were encountered in obtaining definite results from these 



