358 LIBBIE H. HYMAN. 



I., p. 2, of Child's paper we find that of 24 pairs of pieces, the 

 distal oral hydranths emerged first in 14 cases, at the same time 

 as the proximal oral hydranths in 5 cases, and later than the 

 latter in 5 cases. A result which is due to experimental error 

 should vary equally in both directions. It should also be stated 

 that part of the pieces given in this table were regenerating in 

 modified sea-water and not under normal conditions. In regard 

 to Tables II. and III., p. 5, Banus has misrepresented the facts. 

 In these tables the differences between the times of emergence 

 of distal and proximal oral hydranths are less than in the pre- 

 ceding table, although they still vary in the same direction; 

 but it is distinctly stated by Child in the text that the difference 

 is decreased owing to the smaller size of the pieces, and he further 

 shows that with still greater reduction in the length of the pieces, 

 the proximal oral hydranths will emerge first. In short, these 

 experiments were directed towards demonstrating the effect of 

 reduced length on the time of emergence of the oral hydranths, 

 a fact which Banus in quoting them omits to mention. 



After Banus's paper appeared the experiment was repeated at 

 Woods Hole in the summer of 1918 by Dr. W. C. Allee. Dr. 

 Alice was entirely unable to agree with Banus's statements, but 

 found, on the contrary, that the oral hydranths arise earlier on 

 apical than on basal pieces of the stem of Tubularia. He com- 

 municated this result to Professor Child and other members of 

 this laboratory and also showed his experiments to a number of 

 people at Woods Hole. In the summer of 1919, Dr. Allee 

 assigned the experiment to his class in Invertebrate Zoology at 

 Woods Hole. Twenty-seven sets of experiments were performed 

 by the students, each set consisting of from two to eight pairs of 

 pieces. Twenty-four hours after cutting, the apical halves (as 

 indicated by the red color of the regenerating ends) were in 

 advance in twenty-five of the sets, the basal halves in advance in 

 one set, and in the other, there was no difference. Of the 112 

 pairs of pieces cut, 95 of the apical pieces survived, and 71 of the 

 basal pieces. After forty-eight hours, 52 or 55 per cent, of the 

 apical pieces had produced hydranths, while this had occurred 

 in only 15, or 20 per cent, of the basal pieces. It should be 

 stated that the material was not in first-class condition at the 



