CELL DIVISION IN EGGS OF CREPIDULA. 



VIII. Effects of Cabbonic Acid. 



569 







Sea Water. 







No. 



Stage. 







Duration. 



Results. 











Charged . 



Normal. 







1,163 



1-8 cells. 



1 part 



1 part 



28hrs. 



Cell membranes usually granular and wrinkled; lobes 

 and spinning threads present; surface tension reduced; 

 nuclear membrane also wrinkled and lobulated, 

 giving appearance of amitosis; chromatin dense and 

 achromatin scanty in resting nuclei; resting spheres 

 lie at surface of cell, as in normal eggs; mitotic figures 























normal; cleavage very irregular and often suppressed. 













Figs. 119, 120, 122-129, 131. 



1,164 



1-8 cells. 



1 



1 



28hrs. 



Same as preceding. 



1,165 



1-8 cells. 



1 



1 



28hrs. 



Same as preceding. 



1,166 



1-30 cells. 



1 







28 hrs. 



Similar to preceding; resting nuclei much lobulated, as 

 if in amitosis. 



1,167 (1) 



1 cell. 



1 



1 



7hrs. 



1-8 cells; cell membrane wrinkled; yolk cleavage often 

 suppressed; nuclei of macromeres densely chromatic; 

 mitotic figures normal; positions of spheres, nuclei 

 and cytoplasm dependent upon direction of cell 

 constriction. 



(2) 



1 cell. 



1 



1 



28hrs. 



20-40 cells; similar to preceding; many abnormal 

 cleavages due to local reductions of surface tension. 



1,168 (1) 



1-30 cells. 



1 



1 



4Jhrs. 



1-30 cells; in addition to preceding modifications 

 chromosomes may be widely scattered and cytoplasm 

 coarsely granular. 



(2) 



1-30 cells. 



1 



1 



20 hrs. 



4-52 cells; similar to preceding; many karyomeres and 

 irregular nuclei. 



1,169 (1) 



1-2 cells. 



1 



1 



18 hrs. 



1-24 cells; cleavage may be normal or very abnormal; 

 some micromeres and nuclei go through center of egg 

 to vegetal pole; many blastomeres lobulated; cleavage 

 sometimes suppressed; eggs often stick together. 



24-48 cells; macromeres may be separated from one 



(2) 



1-2 cells. 



1 



1 



25hrs. 













another and micromeres may go through center of 













egg to vegetal pole. 



(3) 



1-2 ceUs. 



1 



1 



42hrs. 



64-68 cells; many eggs fused in pairs; fusion always 

 between entomeres; nuclei always at surface and not 

 buried along line of fusion. 













l,169a(l) 



1-4 cells. 



1 



1 



31irs. 



1-4 cells; chromatin clumped in resting nuclei; sphere 

 outlines very distinct, especially on side away from 

 animal pole; chromosomes scattered; in first cleavage 

 yolk lobe and polar bodies are carried in with furrow 

 to Zwischenkorper, and no new membrane is formed 

 until after constriction is completed. 



(2) 



1-4 cells. 



1 



1 



26 hrs. 



8-25 cells; cleavage normal in most eggs; suppressed in 



a few. 

 48-52 cells; normal in most cases; first and second 



(3) 



1—4 cells. 



1 



1 



44hrs. 













cleavages suppressed in a few eggs. 



(4) 



1-4 cells. 



1 



1 



50 hrs. 



52-64 cells; similar to preceding. 



l,169bl) 



1-4 cells. 



1 



1 



6 hrs. 



1-8 cells ; some cleavages suppressed ; many spindles dis- 

 placed and chromosomes scattered; many spindles 

 distorted; many lobes on cells. 



(2) 



1-4 cells. 



1 



1 



24 hrs. 



1-8 cells; similar to preceding; cells and nuclei lobulated; 

 many .scattered chromosomes and karyomeres, sup- 

 pressed cleavages and distorted spindles. 



(3) 



1-4 cells. 



1 



1 



24 hrs. 









Normal 



sea water 



11 hrs. 



8-30 cells; many irregular cleavages with lobulated and 

 separated macromeres. 



(4) 



1-4 cells. 



1 



1 



24 hrs. 









Normal 



sea water 



25 hrs. 



30-50 cells; cleavage very abnormal; many eggs fused. 



(5) 



1-4 cells. 



1 



| 1 



24 hrs. 







Normal 



sea water 



48 hrs. 60-80 cells; very abnormal cleavage; many fused 

 1 eggs. 



