580 



GABRIELE KASS-SIMON 



1. 



I\h30 



N-31 



N33 



N 29 



N 29 



N30 



.75% 



50 °o 



25% 



10% 



°oREG. MEAN 

 ANIMALS 8DT S 



JBT 73.3 98.66 



96.8 44.78 



100 42.36 



96.8 39.87 



100 



JAB 100 



38.39 



26.14 



24 



48 72 96 120 



ONE REGENERAT ED 

 ANIMAL 



ONE NON-REGENERATED 

 ANIMAL 



Fig. 5. 



Basai Plate Differentiation Time at Various Axial Levels. The times 

 (in hours) at which basai plates were completely regenerated. (BDT= 

 Basai Plate Differentiation Time. The data from table 6 is pooled for 

 each axial level. JBT=Just Below Tentacles. JAB=Just Above 

 Basai Plate). 



IV. HYDRANTH REGENERATION IN BUDDING ANIMALS 



(a) Introduction 



The présence of a bud has been variously considered to inhibit, either directly 

 (Burnett, 1961 b) or by compétition (Goetsch, 1929) the régénération of a 

 hydranth by the mother animal. On the one hand, the notion of a diffusing 

 inhibitor implies that its effect is inversely proportional to the distance between 

 the site of its production and that of its effect. On the other, the notion of competi- 



