576 



CELL DIVISION IN EGGS OF CREPIDULA 



No 



836 



837 



838 



847 



847a 



No. 



848 



No. 



869 



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



3. KCl Added to Sea Water. 



Stage. 



1-4 cells 



Per 



Cent 



Time in 



Solution. 



Normal S. W 



Results. 



t 



1-4 cells 



9hrs. 



1 cell. 



1-4 cells 



1-4 cells 



H 



9hrs. 



9hrs. 



35 hrs. 



35hrs. 



18 hrs 



H 



5 hrs. 



5 hrs. 



1 



First and second yolk cleavages may be suppressed, 



with formation of polyasters and karyomeres; after 



4-cell stage fewer micromeres than normal may be 



formed, with nuclei far apart. 

 1-4 cells; cleavage largely suppressed, constricted and 



multiple nuclei, with big nucleoli. Figs. 173, 193. 



194. 

 All cleavage suppressed; lobed, constricted, and multiple 



nuclei ; little distinction between plasma and yolk. 

 16 hrs. 1 25-42 cells; a few still in 1-4-cell stage; nuclei may be 



multiple in macromeres and single in micromeres; no 



sharp distinction between yolk and plasma. 

 2-24 cells; yolk cleavage and mitosis in macromeres 



very abnormal; scattered chromosomes, polyasters; 



karyomeres, especially in macromeres. 



16 hrs. 



4. Herbst's Co-free Sea Water* 30.0 g. NaCl 



.8 KCl 



6.6 MgSO* 



962.2 dist. water 



t*H 1 



Per 

 Cent. 



Ti 



Stage, 



Solution. 



1-20 cells. 



18 hrs. 



Normal S . W 



Results. 



hrs. 



1-30 cells; 



sma 



nuclei and spindles 



hat 



D ..runken; cytasters in unsegmented egg, 

 connected with radiations; chromatin is like 

 spireme ; chromosomes fail to fuse in telophase 

 meres; polyasters. Fig. 201. 



5. Cane Sugar Added to Sea Water. 



i 



Stage. 



1 cell 



Per 



Cent 



Time in 



10 



Solution. 



3 hrs. 



Normal S. W. 



Ill hrs. 



Results. 



1-24 cells; many eggs broken; early cleavages irregu 

 lar: scattered chromosomes, karyomeresjpo^sters 



Andrews, E. A 



XIII. Literature. 



1898. Filose Activities in Metazoan Eggs 



Bull 



Baltzer. F 



1908. Ueber mehrpolige Mitosen bei Seeigeleiern. Verh. 

 1911. Zur Kenntnis der Mechanik der Kernteilungfiguren 



med. phys. Ges. Wurzburg, XXXK 

 Arch. Entw. Mech., aaaii. 



Bataillon, E. 



1901. 

 1904. 



La pression osmotique et les grands problemes de la Biologie. 

 Nouveaux essais de Parthenogenese expenmentale chez les 



XVIII. 



Arch. Entw. Mech., XI. 

 vertebras infeneurs. W. f 



* See note, p. 536. 



