480 C. M. CHILD. 



2. A region of injury produced on the side of the stem by short 

 cuts radiating from a center closes less rapidly than the simple 

 transverse cut and in many cases gives rise after closure to a 

 rounded outgrowth which becomes conical and develops into a 

 new hydranth. This hydranth develops a stem at the expense of 

 the old stem and in some cases the new axis determines a new 

 basal end on the opposite side of the piece, thus completing a polar- 

 ity at right angles to the original axis. Occasionally two hy- 

 dranths instead of one are localized by the injury. 



3. The experimental data indicate that the new polarity and 

 symmetry are the necessary consequence of the localization of a 

 center of cellular activity. The radial gradient of decreasing 

 activity from the center peripherally becomes, as growth proceeds, 

 the axial gradient and the radial symmetry is primarily merely 

 a similarity of all radii vertical to the polar axis at any level. 



LITERATURE CITED 

 Child, C. M. 



'05 Form Regulation in Cerianthus. VIII. BIOL. BULL., VIII. 

 '08 Form Regulation in Corianthiis cestuarii. BIOL. BULL., XV. 

 'oga Experimental Control of Certain Regulatory Processes in 



Harenactis attenuta. BIOL. BULL., XVI. 

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Exper. Zool., VII. 

 '10 Further Experiments on Adventitious Reproduction in Harenactis. 



BIOL. BULL., XX. 

 '263 Studies on the Axial Gradients in Corymorpha palma. II. Biol. 



Gen., II. 

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Gen., II. 

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II. Jour. Exper. Zool., XLVIII. 

 Child, C. M., and Hyman, L. H. 

 '26 Studies on the Axial Gradients in Corymorpha palma. I. Biol. 



Gen., II. 

 Loeb, J. 

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Wurzburg. 

 Torrey, H. B. 

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Zool., VI. 



