560 



CELL DIVISION IN EGGS OF CREPIDULA 



II. Eggs Shaken and Fragmented 



No. 



Stage. 





855 



1-4 cells 



Experiment. 





856 



1-8 cells. 



Shaken, then 



teased out of 



capsules. 

 Teased out of 



857 



887 



Ca. 80 cells. 

 1-8 cells. 



capsules. 



888 



889 

 890 



891 

 892 



921 



922 



923 

 924 



925 



926 



927 

 928 

 929 

 930 

 931 



957 



958 



959 



2-4 cells. 



Teased 



out 



of 



2-4 cells 

 2-4 cells 



2-4 cells. 

 1-8 cells. 

 1-4 cells. 



24 cells. 



1-24 cells. 



1-24 cells. 



1-30 cells. 



1-4 cells. 



1-2 cells. 

 1-4 cells. 



4 cells. 



2 cells. 

 1-8 cells. 



2-24 cells 



2-24 cells 



1-4 cells 



capsules. 

 Shaken. 



Shaken hard. 



Shaken hard. 

 Shaken hard. 



Shaken hard. 

 Shaken. 



Shaken. 



Shaken. 

 Shaken. 

 Shaken. 

 Shaken. 

 Shaken. 



Shaken. 



Shaken. 



Shaken. 

 Shaken hard. 

 Shaken and 



pressed. 



Shaken. 



Shaken. 



Shaken. 



Left in 



Normal Sea 



Water. 



3hrs. 



12hrs 



12 hrs 



8hrs 



15 hrs. 



15hrs. 

 24 hrs. 



24 hrs. 



25 hrs. 

 2 hrs. 



2 hrs. 

 4 hrs. 

 4 hrs. 

 4 hrs. 

 4 hrs. 



4 hrs. 



6 hrs. 



6 hrs. 



12 hrs. 



2-12 hrs. 



4 hrs. 



17 hrs. 



24 hrs. 



Results. 



Many isolated blastomeres and fragmented eggs under- 

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



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

 meres show partial cleavage. 

 Early gastrula; normal. 



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

 meres Bhow partial cleavage. 



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

 show partial cleavage, others, not dividing, have 

 large nuclei (synkaryonts) . 



Similar to preceding. 



Ca. 68 cells in normal eggs ; many isolated macromeres 

 and fragmented eggs, some of them showing partial 



cleavage. 

 Similar to preceding 



1 



normal eggs; many 

 8 cells; some isolated macrom 



eggs. Fig. 31. 



a. 30 cells; some fragmented eg| 

 36 cells ; few eggs not destroyc 



fragments 



fragmented 



1-36 cells ; few 



1-36 cells ; egg . . w 



Many isolated blastomeres and egg fragments 



A few isolated blastomeres and fragmented eggs 



spindles out of position in a few cases. 

 Few eggs, showing few changes. 

 1-8 cells; similar to No. 926. 

 Few eggs, showing few changes. 

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



1 



more 



Many egg fragments 



latter undergoing partial cieavage. u nnrmfl i 



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





yolk cleavage. Figs, tu, -*u, ■*• • . _ 0Tt :-i 



1-52 cells; many isolated macromeres sh^Dwmg^pamai 



asters 



44 



