338 L. V. HEILBRUNN. 



5. Acids, alkalies, and certain salt solutions cause the vitelline 

 membrane to swell. 



6. The membrane may be removed from the eggs by shaking, 

 or it may be caused to rupture by immersion in dilute sea-water. 



7. All of the above mentioned treatments produce polar-body 

 formation. All of them free the egg from restraint. 



8. Maturation in Cumingia is not dependent on an increase in 

 oxidations. 



9. Cortical change in Cumingia produces no increase in permea- 

 bility either to dissolved substances' or to water. 



10. The essential features of cortical change in Cumingia are 

 the same as those previously shown for Arbacia. 



BIBLIOGRAPHY. 

 Bataillon, E. 



'12 La parthenogenese des amphibians et la "fecondation chimique" de Loeb 

 (etude analytique). Ann. des Sci. Nat. Zool., Ser. 9, T. 16, pp. 249-307. 

 Gray, J. 



'16 The Electrical Conductivity of Echinoderm Eggs, and its Bearing on the 

 Problems of Fertilization and Artificial Parthenogenesis. Phil. Trans. 

 Roy. Soc., Series B, Vol. 207, pp. 481-529. 

 Heilbrunn, L. V. 



'13 Studies in Artificial Parthenogenesis. I. Membrane Elevation in the 



Arbacia Egg. BIOL. BULL., Vol. 24, pp. 343-361. 

 '15 Studies in Artificial Parthenogenesis. II. Physical Changes in the Egg of 



Arbacia. BIOL. BULL., Vol. 29, pp. 149-203. 

 '17 Maturation and Initiation of Development in Cumingia. Proc. Amer. 



Assn. Anat. Anat., Rec., Vol. n, pp. 362-363. 

 Lillie, F. R. 



'19 Problems of Fertilization. Chicago: The University of Chicago Press. 

 Lillie, R. S. 



'16 Increase of Permeability to Water Following Normal and Artificial Activa- 

 tion in Sea-Urchin Eggs. Am. Journ. of Physiol., Vol. 40, pp. 249-66. 

 '17 The Conditions Determining the Rate of Entrance of Water into Fertilized 

 and Unfertilized Arbacia Eggs, and the General Relation of Permeability 

 to Activation. Ibid., Vol. 43, pp. 43-57. 



'18 The Increase of Permeability to Water in Fertilized Sea-Urchin Eggs and 

 the Influence of Cyanide and Anesthetics upon this Change. Ibid., Vol. 

 45, pp. 406-30. 

 Loeb, J. 



'13 Artificial Parthenogenesis and Fertilization. Chicago: The University of 



Chicago Press. 

 Lyon, E. P. and Shackell, L. F. 



'10 On the Increased Permeability of Sea-Urchin Eggs Following Fertilization. 

 Science, N. S., Vol. 32, pp. 249-251. 



