386 



LIBBIE H. HYMAN. 



experiment, the apical piece was twice as long as the basal. 

 Pieces for the two experiments of each pair were cut from the 

 same lot of stems at the same time and kept under the same 

 conditions. All of the apical pieces were kept in one finger bowl 

 and the basal in another. The method of cutting the pieces for 

 such experiments is given in text-figure 2. All of these experi- 

 ments were performed in December at a temperature of 12 2. 

 The length of the pieces is stated in the table. No experiments 

 were attempted with pieces in which the ratio of length was 

 I : 3 or i : 4, as it is difficult if not impossible to obtain a sufficient 

 number of unbranched stems of the requisite length. 



The data given in Table VI. show quite clearly that an 



TABLE VI. 



RECORDS OF MASS EXPERIMENTS WITH APICAL AND BASAL PIECES OF UNEQUAL 



LENGTH. 



Columns under a and b record number of hydranths emerged at time indicated. 



G. ALTERATION OF THE REGIONAL DIFFERENCES IN RATE OF 



REGENERATION. 



apical piece will regenerate faster than ii basal piece of twice its 

 length, in pieces at least as long as 5 mm. Although the factor of 

 length is of some consequence, the factor of level is of vastly 



