576 



CELL DIVISION IN EGGS OF CREPIDULA. 



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

 3. KCl Added to Sea Water. 



No. 



Stage. 



Per 

 Cent. 



Time in 



Results. 



Solution. 



Normal S. "W. 



836 



837 



838 

 847 



847a 



1-4 cells. 



1-4 cells. 



1 cell. 

 1-4 cells. 



1-4 cells. 



1 

 1* 



14 

 1 



9hrs. 



9hrs. 



9hrs. 

 5 hrs. 



5 hrs. 



35 hrs. 



35 hrs. 



18 hrs. 

 16 hrs. 



16 hrs. 



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. 

 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. 



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

 .8 KCl 



.2.2 dist. water. 



No. 



Stage. 



Per 

 Cent. 



Time in 



Results. 



Solution. 



Normal S. W. 



848 



1-20 cells. 





18 hrs. 



hrs. 



1-30 cells; plasma, nuclei and spindles somewhat 

 shrunken; cytasters in unsegmented egg, always 

 connected with radiations; chromatin is like a coarse 

 spireme; chromosomes fail to fuse in telophase; karyo- 

 meres; polyasters. Fig. 201. 









5. Cane Sugar Added to Sea Water. 



No. 



Stage. 



Per 

 Cent. 



Time in 





Solution . 



Normal S. W. 





869 



1 cell. 



10 



3 hrs. 



11* hrs. 



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

 lar; scattered chromosomes, karyomeres, polyasters . 



XIII. LlTERATUKE. 



Andrews, E. A. 



1898. Filose Activities in Metazoan Eggs. Zool. Bull., II. 



Baltzer, F. 



1908. Ueber mehrpolige Mitosen bei Seeigeleiern. Verh. med. phys. Ges. Wiirzburg, XXXIX. 

 1911. Zur Kenntnis der Mechanik der Kernteilungfiguren. Arch. Entw. Mech., XXXII. 



Bataillon, E. 



1901. La pression osmotique et les grands problemes de la Biologie. Arch. Entw. Mech., XL 

 1904. Nouveaux essais de Parth6nogenese exp6rimentale chez les vert6br6s inferieurs. Id., 

 XVIII. 

 ♦See note, p. 536. 



