572 



GABRIELE KASS-SIMON 



means are depicted in Figure 2. (See also Figure 6.) It will be noted that five of 

 the 49 animais eut at the 25% level, which lies approximately at the juncture of 



N 63 



foREG. ME AN 



ANIMAL5 TOT S 



N61 



N 66 



\ | JBT 100 29.22 



75% 100 35.47 



50% 100 33.68 



N52 



N40 



I_L 



J_L 



I l 



24 48 72 



□ 



96 120 



Fig. 2. 



25% 90.4 46.10 



10 e 



37.5 69.00 



ONE REGENERATED 

 ANIMAL 



ONE NON-REGENERATED 

 ANIMAL 



Time of Tentacle Differentiation at Various Axial Levels. The times (in 

 hours) at which tentacles first appeared on " standard " animais transec- 

 ted at the given axial levels. The data taken from table 1 represents a 

 pooling of the values from the four clones at each level. (TDT= Ten- 

 tacle Differentiation Time. JBT=Just Below Tentacles). 



peduncle and gastric région, failed to regenerate in the allotted time, while at 

 the 10% level, well within the peduncle, 26 out of 41 animais did not regenerate. 

 A significant différence for each of the clones in the mean TDT's exists when the 

 upper four levels are compared: F=2i.7, p < 0.001 (Clone 7a Ç), F=32.0, 



