THE PRODUCTION OF GRAFTED EMBRYOS. 



79 



enough to separate the eggs from one another. The difficulty 

 was overcome by using narrow bore tubes whose inside diameter 

 was about 3 mm. Eggs centrifuged in these tubes within the 

 centrifugal limits already mentioned, gave rise to normal embryos 

 and larvae many of which were agglutinated or fused. 



TABLE III. 



The effect of centrifuging eggs in capillary tubes, after they have been fertilized, 

 and had their membranes removed. 



No. Experiment. 



30-2 Not centrifuged. 



3 Not centrifuged. 



4 Not centrifuged. 



5 Not centrifuged. 



25-30 Centrifuged 30 revol. 



31 Centrifuged 30 revol. 



32 Centrifuged 30 revol. 



33 Centrifuged 30 revol. 



40 Centrifuged 60 revol. 



41 Centrifuged 60 revol. 



42 Centrifuged 60 revol. 



43 Centrifuged 60 revol. 



50 Centrifuged 90 revol. 



51 Centrifuged 90 revol. 



52 Centrifuged 90 revol. 



53 Centrifuged 90 revol. 

 18-29 Not centrifuged. 



30 Not centrifuged. 



31 Not centrifuged. 



32 Not centrifuged. 



33 Not centrifuged. 



34 Not centrifuged. 



35 Not centrifuged. 



Result. 



hr. Same as 



Same as 



hrs. Same 



Kept in capillary 



control. 

 Kept in capillary i hr. 



control. 

 Kept in capillary 



as control. Clusters present. 

 Kept in capillary 18 hrs. Most 

 dead. 



Norm. Clusters present. 

 Norm. Clusters present. 

 Norm, and irregularities. 

 Norm, and irregularities. 

 Norm, and irregularities. 

 Norm, and irregularities. 

 Norm, and irregularities. 

 Norm, and irregularities. 

 Norm, and irregularities. 

 Norm, and irregularities. 

 Nearly all dead. 

 Nearly all dead. 

 Kept in capillary i hr. Norm. 

 Kept in capillary 2 Yi hrs. Norm. 

 Kept in capillary 3 hrs. Plutei 



irreg. 

 Kept in capillary 



norm, plutei. 

 Kept in capillary 



gastrula. 

 Kept in capillary 



early cleavage. 



Kept in capillary 



early cleavage. 



CALCIUM-FREE SEA WATER. 



When eggs with their membranes removed were placed in 

 calcium-free sea water for half an hour, the blastomeres of the 

 two-cell stage separated from one another either completely, 



