4i: 



Ralph S. Lillie 



utes after removal, warmed to 35° for 70 seconds after the indicated 

 intervals in the cyanide sea-water, and then transferred as above 

 to fresh sea-water. The results were as follows: 



A fourth series (August 29) gave an even more striking result. 

 Eggs were placed, 40 minutes after removal, in —-^-^j KCN, warmed 

 to 35° for 70 seconds after the following intervals in this solution, 

 then transferred to normal sea-water which was changed as usual. 

 The control eggs warmed in sea-water at 40, 50 and 60 minutes 

 after removal gave only a few blastulae, the great majority dying 

 and disintegrating at an early stage. In the best of the several 

 sperm-fertilized portions only one-third to one-half of the mature 

 eggs formed blastulae which were largely feeble or otherwise 

 abnormal. The results were as follows : 



35 m. in KCN 



60 m. 



I h. 35 m. 



Next morning the dish was full of vigorous normal-looking blastulae 

 and early gastrulae; condition much better than in the best sperm- 

 fertilized control 



Decidedly less favorable than Experiment i; a good proportion of 

 eggs form larvae, but these are less active and normal than above 



Still less favorable; nevertheless a large proportion have formed 

 larvae; these are largely irregular in form and somewhat feeble 

 in movement 



In each of the above four series of experiments a far larger 

 proportion of eggs produced larvae after treatment with cyanide 

 for an appropriate length of time than after simple warming un- 

 accompanied by such treatment; and the development was more 

 nearly normal and resulted in the production of larger and more 

 vigorous larvae. The results were indeed comparable in the best in- 

 stances to those obtained with normal sperm-fertilization; in fact, in 

 the last two series better conditions were obtained with the artifici- 

 ally fertilized eggs than with those fertilized in the natural manner. 



