Influence of the Nervous System 715 
anterior to x. ‘The strip was without ganglia or cords. When no 
shrinkage took place a new head regenerated. This is in accord 
with conclusions of Experiment 7. 
Experiment ro. By cutting a long V-shaped piece from the 
anterior end, the cephalic ganglia and large parts of the cords c and 
c’ are removed, and a larger portion of the body of the animal is 
left anterior to X. There is great variation in the result. If both 
strips are nearly equally long the animal behaves like those in 
Experiment 8. If one is considerably longer than the other, the 
resulting behavior is like Experiment 7. If both ends slough off, 
no regeneration occurs. 
Experiment rr. When a ,A-shaped piece was cut from the head 
end, at such a level that the ganglia and major part of cords c and 
c’ were removed, a new head was invariably formed. Both cut 
sides of the ( contributed to the formation of the new head. 
Experiment 12. Each longitudinal half of the animal can 
replace the missing half, and thus produce two whole organisms. 
Even when the animal is cut into two unequal parts regeneration 
takes place in each, provided the smaller piece is not too small. 
The exact size below which no regeneration occurs is difficult to 
determine. It is certain however that many such pieces containing 
nearly the whole of one of the nerve cords never regenerate. 
Experiment 13. The animals were cut longitudinally into two 
nearly equal parts and then each half was cut across, either anterior 
to X or posterior to it. More frequently the operations were made 
in the reverse order. The anterior pieces developed into complete 
animals. ‘The posterior parts also developed into complete ani- 
mals provided the cross cut was anterior to X. In other words, 
lateral as well as posterior and anterior regeneration took place. 
When however the cross cut was made posterior to X, all regenera- 
tion even the lateral regeneration was inhibited. 
Experiment 14. The result in the previous experiment stands 
in marked contrast to that obtained after first dividing the animal 
at any level posterior to X, and then cutting the tail across. A 
new tail regenerates. This was pointed out by L. V. Morgan in 
Leptoplana. 
According to the prevailing view we should believe that the 
