54 c. M. CHILD. 



the changes in steepness are great, marked morphological and 

 physiological differences are present. 



4. The facts indicate that the axial gradient is the dynamic 

 basis of morphological and physiological polarity in the ciliate 

 infusoria as well as in other organisms. 



REFERENCES. 

 Child, C. M. 



'12 Studies on the Dynamics of Morphogenesis and Inheritance in Experi- 

 mental Reproduction, IV. Certain Dynamic Factors in the Regulatory 

 Morphogenesis of Planaria dorotocephala in Relation to the Axial Gradient. 

 Journ. Exp. Zool., Vol. XIII., No. i, 1912. 



'133 Certain Dynamic Factors in Experimental Reproduction and their 

 Significance for the Problems of Reproduction and Development. Arch. f. 

 Entwickelungsmech., Bd. XXXV., H. 4, 1913. 



'i3b Studies, etc., V. The Relation between Resistance to Depressing Agents 

 and Rate of Metabolism in Planaria dorotocephala and its Value a? a Method 

 of Investigation. Journ. Exp. Zool., Vol. XIV., No. 2, 1913. 



'130 Studies, etc., VI. The Nature of the Axial Gradients in Planaria and their 

 Relation to Antero-posterior Dominance, Polarity and Symmetry. Arch, 

 f. Entwickelungsmech., Bd. XXXVII., H. i, 1913. 

 Loeb, J. 



'99 Warum ist die Regeneration kernloser Protoplasmastiicke unmoglich oder 



erschwert? Arch. f. Entwickelungsmech., Bd. VIII., H, 4, 1899. 

 Verworn, M. 



'01 Die Physiologische Bedeutung des Zellkerns. Arch. f. d. ges. PhysioL, Bd. 

 LI., 1891. 



'04 Die Lokalisation der Atmung in der Zelle. Festschr. zum siebsigsten 

 Geburtstag von Ernst Haeckel. Jena, 1904. 



