REGENERATION IN HYDRA ATTENUATA 



573 



p < 0.001 (Clone 6 ?), F=7.1, p < 0.001 (Clone 18 F-4.95, p < 0.01 (Clone 

 3a 9)- A s explained on page 5 for statistical treatment, the data from the four 

 clones is not pooled, since the effect of sex on régénération has not been fully 

 clarified. The différences are not linear and are due to différences between JBT and 

 75% and again between 50% and 25%. Animais eut at 50% appear to regenerate 

 somewhat earlier than those eut at 75% but the différence is obviously not signi- 

 ficant. 



2. Final Tentacle Number (FTN) 



The data are given in Table 2 and since no significant différence was found 

 among the four clones at any given level the means of the weighted four clone 

 means are pooled and depicted in Figure 3. The différences within Clones 7a Ç 

 and 3a $ are probably significant: F=3.7 and 3.2, respectively, p < 0.05, while the 

 différence for clone 18 <J is significant at the 1% level of significance (F=5.7). 

 Significance could not be demonstrated for the différences in the remaining clone. 

 From the data in Table 2, it is clear that no différences exist between JBT, 75 % 

 and 50 % levels, and that the real différence is between the FTN's of the 25 % level 

 with respect to those of the 50 % level and above. 



Table 2. 



FTN ( Final Tentacle Number ) . Mean number of tentacles regenerated 120 hours 

 after transection at the various axial levels in each of four clones of standard animais. 

 Values omitted from statistical considération are in brackets. JBT=Just Below Tentacles. 

 N= Number of Regenerated Animais. 





Clone 7a ? 



Clone 6 ? 



Clone 18 3 



Clone 3a ? 



JBT 



N= 



5.37 ± 0.64 



24 



4.46 ± 0.52 

 13 



5.00 ± 0.63 

 10 



4.54 ± 0.43 



14 



75% 



N= 



5.16 ± 0.69 

 18 



4.06 ± 0.69 

 16 



4.33 ± 1.09 

 12 



5.00 ± 0.79 

 10 



50% 



N= 



5.24 ± 1.14 

 21 



4.15 ± 0.62 

 13 



4.33 ± 0.87 

 12 



5.00 ± 0.67 

 12 



25% 



N= 



3.50 ± 0.89 

 16 



3.40 ± 0.92 

 10 



2.40 ± 0.63 

 10 



3.50 ± 0.63 

 8 



10% 



N= 



(1.66 ± 1.14) 

 3 



3.14 ± 0.59 

 7 



(2.75 ± 0.86) 

 4 



(2.50 ± 0.50) 

 4 



