

Vol. V. August, 1903. No. 3 



BIOLOGICAL BULLETIN. 



ON THE CONDITIONS GOVERNING THE PRODUC- 

 TION OF ARTIFICIAL PARTHENOGENESIS 



IN ARBACIA. 



S. J. HUNTER. 



In a previous paper * it was shown that sea-water concentrated 

 by evaporation to a definite volume would produce partheno- 

 genesis in eggs of the sea-urchin, Arbacia, subjected to its 

 influence for a given length of time. During the continuation of 

 these experiments for the purpose, primarily, of observing the 

 morphological phenomena there has become evident a series 01 

 conditions necessary to a high ratio of parthenogenetic develop- 

 ment. These conditions are briefly -- purity of solutions, stage 

 of development of ovarian eggs when placed in the concentrated 

 sea-water, length of time the eggs are to remain in this solution, 

 temperature of solutions. This article is based upon observa- 

 tions on eighty-three experiments, fourteen of them performed 

 between July 25 and August 14, 1901, and sixty-nine between 

 July 4 and August 15, 1902. The work of both seasons 

 was pursued at the Marine Biological Laboratory, Woods 

 Holl. In every instance the eggs for each experiment were 

 taken from one female only. In this brief preliminary account 

 detailed references to individual experiments are in some cases 

 given, not to illustrate the condition peculiar to that experiment 

 alone, but rather to set forth prevailing conditions. 



Solutions. These are rendered ineffective, (i) by the presence 

 of foreign substances ; (2) spermatozoa ; (3) excessive number 

 of eggs. The eggs of Arbacia are extremely sensitive to foreign 

 substances liable to be introduced by the use of glassware not 

 thoroughly cleansed or glassware previously used as receptacles 



1 Hunter, American Journal of Physiology, VI., 1901, p. 177. 



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