Compensatory Regulation. 



13 



viduals of 19 or 20 mm. are reached when the regeneration length 

 for 46 days arrives at a second minimum. A similar relation 

 between rate of regeneration and disk diameter is shown in 



Fig- 3- . 



In Fig. 3 all the data for the Series I, II, III and IV are included. 

 It was not, however, possible to put in the individual measure- 

 ments without confusing the general effect of the curves. There- 

 fore Series I and II are combined in one curve (the unbroken 



Fig. 4. 



Brittle-star, Ophioglypha lacertosa. Left figure — Typical specimen with one regenerating arm. 

 Right figure — Typical specimen with four regenerating arms. Both 46 days after operation. In left 

 specimen two unoperated arms are shortened for lack of space in figure ( X i o). 



line) and Series III and IV in another (the dotted line). As the 

 individual disk diameters are not exactly equivalent in the different 

 series, it was found convenient in taking the averages for the com- 

 bination curves to use arbitrarily disk diameters equal to whole 

 millimeters as the points for comparison. The values for such 

 disk diameters are obtained from the separate curves constructed 

 from the individual measurements for each series according to the 

 method shown in Fig. 2. The average curve for Series I and IV 

 in Fig. 2 would be one equidistant between them. The combina- 

 tion curves for Series I and II and Series III and IV, as given in 

 Fig. 3, are constructed on this basis. The unbroken line gives 



