268 MARIO GARCIA-BANUS 



this may serve the experiment recorded in table 1. The size of 

 both pieces was 20 mm., so that they were long enough to show a 

 marked difference according to Child's opinion. Of the twenty 

 stems included in this experiment, in eight of them the oral 

 hydranth of the apical piece appeared first, but there were seven 

 cases in which the oral hydranth of the basal piece was the first 

 to appear and four cases in which they both appeared at the same 

 time. The averages of the time of appearance are 77.6 hours for 

 the oral hydranths of the apical pieces and 76.1 hours for the oral 

 hydranths of the basal pieces. The difference is even slightly in 

 favor of the oral hydranth of the basal piece, but it is so small 

 that it is within the limits of error or of individual variation. 



In a second group of experiments the stems were cut into three 

 pieces of equal length. The pieces in this case were each 10 mm. 

 long and the results are similar to those of the other series. 



The experiment in table 2 may serve as an example. There 

 are in this case ten stems in which the oral hydranth of the third 

 and most basal pieces emerges before the corresponding hydranths 

 of the most apical pieces, while there are only five stems in which 

 the oral hydranth of the most apical piece is the first to appear 

 and there are two cases in which both appear at the same time. 

 If we compare the apical piece with the middle piece, the results 

 are the same; in seven cases out of the twenty, the oral hydranth 

 of the middle piece is the first to appear, while there are only two 

 cases in which the contrary happens, and six cases in which both 

 appear at the same time. 



The averages in this experiment are: 78.6 hours for the oral 

 hydranths of the apical piece, 77.8 for those of the middle piece, 

 and 74.2 for those of the basal pieces. This shows again that the 

 slight difference in the time of appearance turns out to be in the 

 opposite sense of what we ought to expect from Child's theories. 

 We have made several series of this type with similar results, 

 and in some cases the differences in favor of the basal pieces were 

 even greater than in the case just shown. For instance, in one 

 of these experiments in which twenty stems were cut into three 

 pieces of 10 mm. each, the averages for the time of emergence of 



