2 8o THE ORIGIN OF THE NERVOUS SYSTEM 



HERTWIG, O. and R. 



1878. Das Nervensystem und die Sinnesorgane der Medusen. 



Leipzig. 

 HERTWIG, R. 



1905. A Manual of Zoology. English translation. New 

 York. 



HILL, A. V. 



1912. "Absence of Temperature Changes During the 

 Transmission of a Nervous Impulse," Jour. PhysioL, 

 XLIII. 

 HILL, C. 



1900. "Developmental History of the Primary Segments of 

 the Vertebrate Head," Zool. Jahrbiicher, Abt. f. 

 Anat. und OnL, XIV. 

 His, W. 



1889. "Die Neuroblasten und deren Entstehung im embry- 

 onalen Mark," Arch. f. Anat. u. Entwicklungsges., 

 Jahrgang 1889. 

 HYDE, IDA H. 



1904. "Differences in Electrical Potential in Developing 



Eggs," Amer. Jour. PhysioL, XII. 

 HYMAN, L. H. 



1916. "An Analysis of the Process of Regeneration in Cer- 



tain Microdrilous 01igochaetes,"/owr.x/>. Zool., XX. 



1917. "Metabolic Gradients in Amoeba and Their Relation 



to the Mechanism of Amoeboid Movement," Jour. 

 Exp. Zool., XXIV. 



1918. "Suggestions Regarding the Causes of Bioelectric 



Phenomena," Science, XL VIII. 



1919. "On the Action of Certain Substances on Oxygen 



Consumption. II. Action of Potassium Cyanide 



on Planaria" Amer. Jour. PhysioL, XL VIII. 

 JOHNSON, MYRTLE E. A. 



1910. "Quantitative Study of the Development of -the 



Salpa Chain in Salpa fusiformis-uncinata." Univ. 



Col. Pub., Zool., VI. 

 JOHNSTON, J. B. 



1906. The Nervous System of Vertebrates. Philadelphia. 



