PROTOPLASMIC MOVEMENT. 



79 



b. Movements during Cleavage. 



It is, however, in the cleavage cells that I have found the 

 most unmistakable evidences of the definite and orderly move- 

 ments of cell contents. In the first cleavage the spindle lies at 





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Wig> 



rt:$y o 



Hio^rjob 



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 -ffirsQV 



FIG. 4. 



FIGS. 3 AND 4. Sections of eggs of C. plana, showing anaphase and telephase 

 of first cleavage. 



right angles to the chief axis of the egg, and the centrosomes 

 are no nearer the surface of the egg than is the middle of the 

 spindle (Figs. 1-3). As the daughter-nuclei pass into the rest- 

 ing phase, however, the centrosomes are transformed into cen- 



