so 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[50 



TABLE 33 



Amblystoma punctatum Series 3962-3999 Age factor eliminated 



Comparison of first and second regenerations 



Eleven days 



Experiment V Amblystoma punctatum Series 6042-6100F 

 This series was devised for a study of the effect of repeated removal 

 of the tail upon the rate of metamorphosis. The removed tails were 

 preserved and they give some data on the comparison of successive 

 regenerations. The interest of the results lies in the fact that the suc- 

 cessive regenerations are compared within single individuals. Thus the 

 effect of the age factor is not eliminated. Environmental differences 

 such as those of temperature may also be factors. 



The eggs were hatched on March 25 to 29, 1915. Approxi- 

 mately one-half in length of the tail was removed in each of the indi- 



