574 



CELL DIVISION IN EGGS OF CREPIDULA 



> 



No. 



970 



971 



972 



973 



974 



975 

 976 

 977 



978 

 979 

 980 



981 



982 



983 



984 



985 



986 



987 



X. Effects of Hypertonic Sea Water. — {Continued.) 



1. NaCl Added to Sea Water. 



Stage. 



Per 



Cent. 



4-12 cells. 



4-12 cells. 



4r-12 cells. 



2-20 cells. 



2-20 cells. 



2-20 cells. 

 2-20 cells. 

 2-20 cells. 





2-20 cells. 

 2-20 cells. 

 2-20 cells. 



1-20 cells. 





1-20 cells. 



1-20 cells. 



1-20 cells. 



2-20 cells. 



988 (1) 



2-20 cells. 



lcell. 



1-4 cells 



(2) 



(3) 

 989 (1) 



(2) 

 (3) 



1-4 cells. 

 1-4 cells. 



lcell. 2d 

 Maturation! 



1-4 cells. 



1-4 cells. 



990 (1) 



(2) 

 (3) 



1-4 cells. 



(4) 

 (5) 



1-4 cells 

 1-4 cells 



1-4 cells. 

 1-4 cells. 



2 



2 



2 



3 



3 



3 

 3 

 4 



4 



4 

 4 



5 



5 



5 



5 



6 



6 



6 



1 



1 



1 

 1 



1 



1 



4 



1 

 4 



1 

 1 



Time in 



Solution. 



16hrs. 



16hrs. 



16hrs. 



Results. 



Normal S. W 



lhr. 



Ihr. 



lhr. 

 lhr. 

 lhr. 



lhr. 

 lhr. 

 lhr. 



|hr. 



ihr. 

 |hr. 

 |hr. 



|hr. 



|hr. 



ihr. 

 lhr. 



|hr. 



2 hrs. 



4 hrs. 



5 hrs. 

 4| hrs. 



4| hrs. 

 4| hrs. 



2|hrs. 



2|hrs. 

 2|hrs. 



Ohrs 



12 hrs 



24 hrs 



lhr. 



16 hrs. 



24 hrs. 



39 hrs. 



lhr. 



16 hrs. 

 24 hrs. 

 39 hrs. 



2 hrs. 



18 hrs. 



24 hrs. 



40 hrs. 



2 hrs. 



18 hrs. 



24 hrs. 



Ohrs. 



Ohrs. 

 Ohrs. 



Ohrs. 



Ohrs. 



13 hrs. 



13* hrs. 



13Jhrs. 

 24 hrs. 



2| hrs. 24 hrs. 

 2| hrs. I 36 hrs. 



4-12 cells; similar to preceding, but modifications more 

 pronounced. 



4-12 cells; great numbers of karyomeres and con- 

 stricted nuclei, polyasters. 



4-20 cells; very abnormal cleavage; yolk cleavage some- 

 times suppressed, sometimes increased; many poly- 

 asters and karyomeres. Figs. 220, 223. 



2-20 cells; nearly normal; few cells show any signs of 

 plasmolysis. 



24-44 cells ; mostly normal ; in a few eggs yolk cleavage 

 suppressed, polyasters and karyomeres. 



30-52 cells ; similar to preceding. 



60-70 cells; almost all normal; a few karyomeres. 



2-20 cells; plasma, nuclei, spindles are normal; have 

 recovered from plasmolysi 



20-50 cells; plasma, nuclei and spindle normal. 



20-60 cells ; chiefly normal ; a few karyomeres. 



60-70 cells ; chiefly normal ; a few degenerating mitotic 

 figures which never recovered ; few karyomeres. 



1-20 cells; chiefly normal; few signs of plasmolysis; a few 

 chromatic connections between daughter nuclei. 



24-44 cells; chiefly normal; no polyasters or karyo- 

 meres. 



2-52 cells; mainly normal; some earlier stages ab- 

 normal, with suppressed or increased yolk cleavage, 

 polyasters and karyomeres. 



60-70 cells, mainly normal ; a few abnormalities of earlier 



ires 



stages similar to preceding. 

 8-24 cells, mainly normal; plasma, 



spindles show no trace of plasmolysis. 

 2-40 cells, mainly normal; some early stages show 



suppression of yolk cleavage, with polyasters and 



karyomeres ; later stages are normal 



1-4 cells; suppressed cleavag 



polyasters, kary 



meres 



1-4 cells; no cleavage; nuclei and spindles shrunken, 

 achromatin withdrawn from radiations into spindle 

 leaving isolated portions of achromatin, wnicn 



become cytasters. 

 1-4 cells ; similar to preceding. 

 1-4 cells ; similar to preceding. 

 1 cell; nuclei and spindles shrunken; cytasters. 



1-i cells; plasma, nuclei and spindles shrunken; few, if 



l-Ru^^u^ressed and unequal cleavage i tf yolk; 

 polyasters, Myomeres; enormous asters surrounded 



manv chromosomes 



chromatic con- 



2-16 cells; scattered chromosomes, 

 nections between daughter nuclei ; polyasters, Karyo- 

 meres, big nuclei and nucleoli. 

 24-44 cells; increased cleavage of yolk. d 



1-24 cells; yolk cleavage may be suppled m lstan^ 

 2d cleavages, increased in later cleavages, polyasters, 

 karyomeres ; no normal mitoses. 



52-60 cells; mostly normal. 



68-76 cells : a few karyomeresandpolyasie 



