CELL DIVISION IN EGGS OF CREPIDULA. 



573 



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

 1. NaCl Added to Sea Water. 



827 



829 

 830 



831 

 832 



840 



843 



844 

 861 



862 

 863 



864 



865 



965 

 966 

 967 



1-2 cells. 

 1-20 cells. 



1-20 cells. 



1-20 ceUs. 

 1-20 cells. 



1-20 cells. 

 1-20 cells. 



1-4 cells. 



1-4 cells. 



1-4 cells. 



1-4 cells. 

 1-4 cells. 



1 cell. 



1-4 cells. 



1-4 cells. 



1-4 cells. 



20-30 cells. 

 20-30 cells. 

 1-20 cells. 



1-20 cells. 

 4-12 ceUs. 



Solution. Normal S. W. 



16hrs. 

 9hrs. 



2 hrs. 



9hrs. 

 9 hrs. 



2 hrs. 

 2 hrs. 



6 hrs. 



6 hrs. 



6 hrs. 



6 hrs. 

 13 hrs. 



4 hrs. 

 2\ hrs. 



2 hrs. 

 3ihrs. 



2 hrs. 



3 hrs. 

 16 hrs. 

 16 hrs. 



16 hrs. 



3 hrs. 



23 hrs. 

 8 hrs. 



6ihrs. 



18 hrs. 

 32 hrs. 



6£hrs. 

 6} hrs. 



20 hrs. 



20 hrs. 



15 hrs. 



15 hrs. 

 Ohrs. 



10 hrs. 



10 hrs. 



10 hrs. 

 10 hrs. 



10 hrs. 



Ohrs. 

 Ohrs. 

 12 hrs. 



24 hrs. 

 Ohrs. 



1-2 cells; no cleavage; karyomeres, polyasters; some 

 nuclei large, thin walled and achromatic, others 

 contain large, dense nucleolus; many nuclei con- 

 stricted and lobed as in amitosis. Fig. 202. 



Ca. 2-50 cells; cleavage irregular; yolk cleavage usually 

 suppressed, sometimes increased; karyomeres; many 

 polyasters; later stages less modified than earlier 

 ones. Figs. 203, 206. 



1-24 cells; very abnormal cleavage; yolk cleavage sup- 

 pressed, plasma cleavage active; polyasters, scattered 

 chromosomes, karyomeres. Fig. 222. 



Ca. 1-60 cells; cleavage very irregular; yolk divides 

 seldom; many polyasters, karyomeres. 



Ca. 1-70 cells; cleavage nearly suppressed; many poly- 

 asters, karyomeres, which stain faintly; clear, un- 

 stained nucleoli. Fig. 207. 



Ca. 1-30 cells; no polyasters or karyomeres, chromo- 

 somes widely scattered; nuclei flattened in polar axis. 



1-20 cells; yolk cleavage suppressed; karyomeres, 

 polyasters; nuclei flattened in polar axis; advanced 

 stages nearly normal. 



Ca. 1-30 cells; yolk cleavage suppressed; polyasters, 

 karyomeres; scattered chromosomes; bunch of mi- 

 cromeres on unsegmented yolk. 



Ca. 1-30 cells; yolk cleavage suppressed; polyasters, 

 karyomeres; chromosomes widely scattered. 



30-40 cells; yolk cleavage suppressed; polyasters, karyo- 

 meres; more advanced stages normal. Fig. 205. 



Ca. 2-40 cells; similar to preceding. 



20-40 cells; almost normal; yolk cleavage occurs; few 

 polyasters. 



Ca. 2-24 cells; yolk cleavage more or less suppressed; 

 many polyasters and karyomeres; heaps of micro- 

 meres. 



1-25 cells; advanced stages normal; yolk cleavage sup- 

 pressed; many polyasters and heaps of micromeres. 

 Figs. 204, 213. 



Ca. 1-30 cells; cleavage irregular; yolk cleavage more 

 or less suppressed; many polyasters and karyomeres 

 Fig. 211. 



Ca. 1-30 cells; cleavage less irregular than preceding; 

 few polyasters and karyomeres; later stages normal. 

 Figs. 209, 212. 



20-30 cells; plasma, nuclei and spindles shrunken and 

 plasmolyzed. 



20-36 cells; little if any cleavage; plasma, nuclei, and 

 spindles much shrunken and plasmolyzed. 



Ca. 1-40 cells; earlier stages show suppressed, or in- 

 creased, yolk cleavage ; polyasters, and karyo- 

 meres; scattered chromosomes, chromatic connec- 

 tions between daughter nuclei; older stages less 

 abnormal. 



1-64 cells; abnormalities similar to preceding; some 

 eggs fused together, others with isolated macromeres. 



4-12 cells; plasma, nuclei and spindles shrunken; in 

 resting nuclei chromatin clumped in middle of 

 vesicle of achromatin; in mitosis amphiaster lies in 

 definite area of achromatin; plasma gathers in 

 cleavage furrows. 



