EXPERIMENTAL LOCALIZATION OF NEW AXES IN 



CORYMORPHA WITHOUT OBLITERATION OF 



THE ORIGINAL POLARITY. 



C. M CHILD, 



HULL ZOOLOGICAL LABORATORY, THE UNIVERSITY OF CHICAGO. 



The various lines of evidence demonstrating the existence of 

 physiological gradients in Corymorpha have been considered in 

 earlier papers (Child and Hyman, '26, Child, '260, '26^). In the 

 last of these papers it was shown that the differential resulting 

 from contact of one end of a stem piece with the bottom and free 

 exposure of the other may determine the one as basal, the other as 

 apical, irrespective of the original polarity. In accordance with 

 this fact it was shown that in pieces undergoing reconstitution on 

 the bottom the bipolar frequency is lower and the unipolar fre- 

 quency higher than in those supported on loose cotton near the 

 surface of the water so that the ends are more nearly equally ex- 

 posed. In other papers it was shown that pieces after subjection 

 to various inhibiting agents may develop new polarities and sym- 

 metries quite independent of the original axes and of the cut ends 

 (Child, '270, 6). Apparently the inhibiting agents decrease or 

 obliterate the original polarity and symmetry and the localizing 

 influence of the cut ends and under these conditions the differential 

 of position becomes more effective in localizing apical ends on 

 the free surface and basal ends on the surface in contact or near 

 the bottom. 



The present paper is concerned with some further experiments 

 on the determination of new polarities. In these experiments the 

 new axes are localized as centers of high metabolic activity and 

 growth without obliterating the original polarity. 



EXPERIMENTAL. 



No indication of development of new hydranths by budding has 

 been observed in Corymorpha. Among thousands of individuals 



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