Artificial Parthenogenesis in Starfish Eggs 



425 



TABLE XIII 



September 10, IQOJ. Eggs were removed at 10:30 a.m.; the majority underwent maturation. After 4^ 

 minutes the eggs were warmed to 55° for 'JO seconds as usual; a portion {for control) was placed 

 immediately in normal sea-water; the remainder in ^^q KCN solution, whence, after the intervals 

 indicated, portions were transferred to sea-water 



The Sperm-fertilized control (sperm added 40 m. after removal) gave a large proportion of gastrulae 

 largely abnormal — irregularly shaped, thick-walled, or sluggish. Very few have gastrulated by 24 

 hours. 



Here also a decided increase in favorability followed after- 

 exposure to the cyanide solution for a not too prolonged period. 

 The results however were less favorable than in the experiments 

 where eggs were exposed to cyanide for some time previously to 

 warming and were warmed in the solution. We may infer that 

 while suppression of oxidations for a certain period after warming 

 is favorable to development in eggs which have previously been 

 well exposed to oxygen, this treatment differs from the preceding 

 in certain very essential particulars, the nature of which requires 

 further analysis. Treatment with cyanide previously as well as 

 subsequently to the momentary warming is essential if the most 

 favorable conditions are to be attained. 



On reviewing the general outcome of the experiments described 

 in this section we are led, first, to the conclusion that the entire 

 series of events leading to the initiation of development in these 

 eggs includes the changes preceding and following the warming 



