14 



SEEGIUS MORGULIS 



decapitation upon posterior regeneration from the very beginning 

 of the process. As will be seen from table 5, in which are given 

 the results of this experiment, the number of worms proliferating 

 new tissue two days after the operation (August 6) is twice as 

 great in the control as in the case of the decapitated worms, 

 being 82 per cent of the former and only 42 per cent of the latter. 

 Four days after the operation (August 8) the detrimental influ- 

 ence of the extra operation upon the regeneration of the tail is 

 still apparent, but after a week's time the difference between 

 control and decapitated worms disappears almost entirely. 



To sum up the results of the above investigation, it may be 

 said that the additional mutilation of the head in Podarke obscura 

 causes a depressing effect upon the tail regeneration, which is 

 expressed either in a smaller number of regenerated segments or 

 in a greater frequency of regenerated tails with few segments. 

 The effect, however, wears off as the time of regeneration is pro- 

 tracted, and is the more pronounced the more anterior the level, 

 i.e. the shorter the moiety of the worm from which regeneration 



TABLE 5 

 August 4 — September 2 



