ARTIFICIAL PRODUCTION OF NORMAL LARV.E 603 



sea-water. At 1:15 all the eggs were examined again. In 

 lots 3 to 7 many eggs were segmented into from 2 to 16 

 cells. The sixteen-cell stages were only found in lot 4. The 

 rest had not gone beyond the eight-cell stage. In lot 2 very 

 few eggs had segmented; in lot 1 all the eggs were seg- 

 mented. No egg had a membrane. Another examination 

 of the eggs was made at 3:05. In lot 1 about 1 per cent, 

 of the eggs was segmented in 2 cells; in lot 2 about 5 per 

 cent, of the eggs were divided, most of them into 2, some of 

 them, however, into 8 or even 16 cells. In lot 3 about 20 

 per cent, segmented. Some had reached the thirty-two-cell 

 stage. In lot 4 more than 20 per cent, were segmented, 

 some as far as into 32 cells. In lot 5 almost every second 

 egg was segmented. Some had reached about the thirty- 

 two-cell stage. The same was true of lots 6 and 7. In lot 

 8 many eggs had segmented, but they were far behind in 

 their development. No egg had a membrane. The single 

 cells did not stick as closely together as they did in the 

 fertilized egg with the membrane. I was afraid from the 

 appearance of the eggs, that they would not give rise to 

 blastula3, inasmuch as it seemed as though the cleavage cells 

 would all fall apart. 



The eggs were not examined until the next morning. In 

 lots 1 and 8 there were practically no blastulaB in motion, 

 or if there were any they escaped my observation. In lot 7 

 I found a small number of blastula3. In lots 3, 4, 5, and 6 

 the water at the bottom of the dish was teeming with blastula3, 

 which with their irregular outlines and the variation in size 

 betrayed clearly that they had developed from eggs without 

 a membrane. 



In the afternoon I found living larvae only in lots 3, 4, 

 5, and 6. Some larva? seemed to be in a gastrula stage, and 

 some even in the transitional stage to the pluteus form. 

 Many had died, and this accounted perhaps for the fact that 



