560 



CELL DIVISION IN EGGS OF CREPIDULA. 







II. 



3ggs Shaken and Fragmented. 



No. 



Stage. 



Experiment. 



Left in 



Normal Sea 



Water. 



Results. 



855 



1-4 cells. 



Shaken, then 

 teased out of 

 capsules. 



3hrs. 



Many isolated blastomeres and fragmented eggs under- 

 going partial cleavage. Figs. 32, 33, 35. 



856 



1-8 cells. 



Teased out of 

 capsules. 



12hrs. 



8-30 cells, normal development; a few isolated macro- 

 meres show partial cleavage. 



857 



Ca. 80 cells. 



Teased out of 

 capsules. 



12 hrs. 



Early gastrula; normal. 



887 



1-8 cells. 



Shaken. 



8hrs. 



20-29 cell stage of normal eggs; many isolated macro- 

 meres show partial cleavage. 



888 



2-4 cells. 



Shaken hard. 



15 hrs. 



Ca. 50 cells, of normal eggs; many isolated macromeres 

 show partial cleavage, others, not dividing, have 

 large nuclei (synkaryonts). 



889 



2-4 cells. 



Shaken hard. 



15 hrs. 



Similar to preceding. 



890 



2-4 cells. 



Shaken hard. 



24 hrs. 



Ca. 68 cells in normal eggs; many isolated macromeres 

 and fragmented eggs, some of them showing partial 

 cleavage. 



Similar to preceding. 



891 



2-4 cells. 



Shaken hard. 



24 hrs. 



892 



1-8 cells. 



Shaken. 



25 hrs. 



52-70 cells in normal eggs; many partial eggs. 



921 



1-4 cells. 



Shaken. 



2 hrs. 



1-8 cells; some isolated macromeres and fragmented 

 eggs. Fig. 31. 



922 



24 cells. 



Shaken. 



2 hrs. 



Ca. 30 cells; some fragmented eggs. 



923 



1-24 cells. 



Shaken. 



4 hrs. 



1-36 cells; few eggs not destroyed. 



924 



1-24 cells. 



Shaken. 



4 hrs. 



1-36 cells; egg fragments. 



925 



1-30 cells. 



Shaken. 



4 hrs. 



Many isolated blastomeres and egg fragments. 



926 



1-4 cells. 



Shaken. 



4 hrs. 



A few isolated blastomeres and fragmented eggs, 

 spindles out of position in a few cases. 



927 



1-2 cells. 



Shaken. 



4 hrs. 



Few eggs, showing few changes. 



928 



1—4 cells. 



Shaken. 



6 hrs. 



1-8 cells; similar to No. 926. 



929 



4 cells. 



Shaken. 



6 hrs. 



Few eggs, showing few changes. 



930 



2 cells. 



Shaken hard. 



12 hrs. 



16-24 cells; few eggs left; a few isolated macromeres. 



931 



1-8 cells. 



Shaken and 

 pressed. 

 Shaken. 



2-12 hrs. 



1-24 cells; more than 4 macromeres. 



957 



2-24 cells. 



4 hrs. 



Many egg fragments and isolated macromeres, the 











latter undergoing partial cleavage. 



958 



2-24 cells. 



Shaken. 



17 hrs. 



24-68 cells; many partial eggs, some showing abnormal 

 yolk cleavage. Figs. 40, 43, 47. 



959 



1-4 cells. 



Shaken. 



24 hrs. 



1-52 cells; many isolated macromeres showing partial 

 cleavage; in some macromeres cleavage suppressed, 

 but many nuclei and asters. Fig. 44. 



