CELL DIVISION IN EGGS OF CREPIDULA. 



567 



VI. Effects of Ether Added to Sea Wateh. 



No. 



Stage. 



Strength, 

 Per Cent. 



Duration. 



Results. 



800 



1-8 cells. 



1 



lhr. 



No modifications, except that cytoplasm and yolk are not 



sharply separated. 

 4-16 cells ; similar to preceding. Control in 2-8 cells. 



801 



1-8 cells. 



I 



5Jhrs. 



803 



1-8 cells. 



1 



5£ hrs. 



4-16 cells; similar to No. 800. 



818 



2-20 cells. 



1 



25 hrs. 



Ca. 52 cells; archiplasm gathered around sphere or nucleus; 

 chromatin clumped; chromosomes scattered and spindle 

 fibers gone; no signs of amitosis. 



819 



2-20 cells. 



1 



25 hrs. 



Similar to preceding; control in 52 cell stage. 



877 



1-8 cells. 



3 



ihr. 



Cleavage stopped; yolk and cytoplasm intermingle; archiplasm 

 gathers along cleavage furrows; chromosomes scattered; 



















spindle fibers indistinct. 



878 



1-8 cells. 



3 



3 hrs. 



Similar to preceding; sphere granules widely scattered; centro- 







(Norma 



IS. W. 



somes large; chromatin clumped in resting nuclei; archiplasm 







6h 



rs.) 



gathers in cleavage furrows; blastomeres may separate. 



1,180 (1) 



1-2 cells. 



2 



2 hrs. 



Many lobes and deep furrows in resting stages which bear no 

 constant relations to egg axes or nuclei; clear plasma 

 bounds furrows; mitotic figures approximately normal, 

 spindle fibers distinct. 



(2) 



J 1-2 cells. 



2 



6 hrs. 



4-16 cells; many eggs normal; a few show large polar bodies 

 and many macromeres; mitotic figures normal. All ether 



















had evaporated before close of experiment. 



1,181 (1) 



1-20 ceUs. 



1 



lhr. 



Cleavage and mitotic figures entirely normal; eggs stain 



diffusely. 

 16-52 cells; cleavage and mitoses approximately normal; 



(2) 





1 



16 hrs. 











eggs are swollen and stain diffusely; deeply staining 











granules between yolk spheres. 



VII. Effects of Reduced Oxtgbn Tension. 



1. Sea Water Boiled and Cooled. 



a. In Open Bottles. 



No. 



Stage. 



Duration. 



a No ™ al 1 Results. 

 Sea Water. 



935 



1-2 cells. 



12 hrs. 



hrs. 16-30 cells, normal. 





936 



16-24 cells. 



12 hrs. 



hrs. Ca. 50 cells; normal. 





937 



24-30 cells. 



12 hrs. 



Ohrs. 



Ca. 64 cells, normal. 





938 



lcell. 



18 hrs. 



Ohrs. 



25-60 cells, normal. 





939 



4-12 cells. 



18 hrs. 



Ohrs. 



52 cells, normal. 





940 



24-30 cells. 



18 hrs. 



Ohrs. 



Ca. 64 cells, normal. 





947 



IceU. 



48 hrs. 



Ohrs. 



1-30 cells; framboisia; fusing eggs; many dead. 





948 



4-12 cells. 



48 hrs. 



Ohrs. 



52-70 cells; framboisia; isolated macromeres; many dead. 





949 



24-30 cells. 



48 hrs. 



Ohrs. 



64-86 cells; similar to preceding. 





950 



1-16 cells. 



4 hrs. 



Ohrs. 



2-20 cells, normal. 





951 



1-16 cells. 



17 hrs. 



Ohrs. 



48-60 cells, nearly normal; some chromosomes scattered, 

 resting nuclei tabulated or multiple. 



and some 



952 



1-16 cells. 



24 hrs. 



Ohrs. 



52-70 cells, nearly normal. 





953 



1-16 ceUs. 



40 hrs. 



Ohrs. 



64^86 cells, nearly normal; sometimes only one blastomere of 2-cell 











stage develops. 





