Compensatory Regulation. , 95 



But if we consider the matter from the second point of view, 

 namely, of the influence of the presence of another similar and 

 opposite organ upon the regenerating tissue, the apparent anomaly 

 of the case is cleared up to a great extent. For it is seen that in 

 the first case (Cu alone removed) we have an uninjured opposite 

 large snapping chela to retard the growth of the regenerating 

 cutting chela. In the second case (Sn alone removed) we have 

 as the retarding agent at the beginning merely the smaller Cu 

 chela which, however, gradually undergoes the changes in size 

 and character leading up to the large snapping chela. Finally, 

 in the third case (Cu + Sn removed) we have at the beginning no 

 retarding agent, though gradually the snapping chela develops 

 from this point. 



Expressing this in concise form we have the following relation 

 referring to the retarding agent as indicated by the size and com- 

 plexity of differentiation of the chela situated on the side opposite 

 to the developing cutting chela: 



The snapping chela in the group where the cutting chela alone 

 is removed is greater than the cutting chela developing into a snap- 

 ping chela, as in the group where the snapping chela alone is 

 removed and this in turn is greater than the retarding agent 

 where both chelae are removed, and which amounts to zero at the 

 beginning with a gradual development up to a snapping chela 

 condition. 



And referring to the corresponding regenerated lengths of the 

 cutting chela we have: 



The amount of regeneration of the cutting chela in the first 

 group (Cu alone removed) is less than the amount of regeneration 

 of the cutting chela in the second group (Sn alone removed), and 

 this in turn is less than the amount of regeneration of the cutting 

 chela in the third group where both chelae are removed. 



In graphic form this may be represented as follows: 



Snapping chela [as in Cu group] > 



Cutting chela ( — ► snapping chela) [as in Sn group] ]> 



Zero ( — ► snapping chela) [as in (Cu + Sn) group]. 



Correspondingly, 



Amount of regeneration of cutting chela in Cu group 



< Amount of regeneration of cutting chela in Sn group 



< Amount of regeneration of cutting chela in Cu + Sn group. 



