5IO CM. Child. 



when larger portions are removed the behavior resembles that of 

 pieces w^ithout ganglia. The result is the same whether the part 

 removed be anterior, posterior, or lateral. 



3. In general the experiments indicate that the amount of nerv- 

 ous tissue, I. e., the completeness of the system of connections 

 between parts, rather than the presence of particular regions is 

 the important factor, in determining motor activity. The results 

 support the view that particular centers or regions in which certain 

 stimuli originate do not exist. 



4. In considering relations between the nervous system and 

 morphogenesis it is important to determine whether the relations 

 are direct or indirect, i. e., whether certain nerve stimuli are them- 

 selves formative stimuli or whether the conditions connected with 

 the functioning of the part in a characteristic manner are the true 

 formative stimuli, the nervous stimuli being merely the deter- 

 mining factors of the function. The experiments on Leptoplana 

 indicate that the relation between the nervous system and regener- 

 ation is, at least in large part, indirect. 



5. Posterior regeneration is qualitatively complete at all levels 

 posterior to the cephalic ganglia, though in the absence of food the 

 regenerated part never attains the size of the part removed, i. e.^ 

 the further posterior the level from which regeneration occurs the 

 less is the amount of regeneration. The only satisfactory ex- 

 planation of this difference is the difference in functional stimuli 

 and conditions to which the regenerating part is subjected at 

 different levels; the further posterior the level from which regener- 

 ation occurs the less the new part is used. 



6. The difference in the amount of regeneration at different 

 levels is to a large extent independent of the size of the piece. 

 Small pieces from the anterior region of the body may equal or 

 exceed in amount of posterior regeneration pieces several times as 

 large from the posterior regions. 



7. Comparison of posterior regeneration from a given level in 

 pieces with and those without ganglia shows the following differ- 

 ences; the amount of regeneration is less in the pieces without 

 ganglia, but regeneration is qualitatively complete in both; the 

 form of the regenerated part is less elongated and usually less 



