THE AXIAL GRADIENTS IN HYDROZOA. 



359 



time, and, as I shall show, the difference between the time of 

 regeneration of apical and basal pieces is reduced under such 

 circumstances. Professor Child and I are greatly indebted to 

 Dr. Allee for his interest in the matter, and for his kindness in 

 putting through the experiments. 



In view, therefore, of the overwhelming preponderance of the 

 evidence already at hand in support of the existence of the 



FIGS. 3 AND 4. Diagrams to show method of cutting pieces for experiments 

 given in Table VIII. Figure 3, method for all experiments in Table VIII., except 

 number 36; figure 4, method used for experiment 36. 



regional differences along the axis of Tubularia which are denied 

 by Banus, further experimentation seems superfluous. Under 

 the circumstances, however, a repetition of the experiment has 

 been deemed necessary by various members of this laboratory 

 as an answer to Banus's paper. I therefore undertook to repeat 

 his work and for this purpose made trips to Woods Hole in June, 

 and in December, 1919. The results were identical at both 



