FACTORS IN ONTOGENY 



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FIG. 148. Maturation of the egg of Cyclops (the full number of chromosomes is not 

 shown): A, Chromosomes already split longitudinally; B, chromatin masses with 

 indication of transverse fission to form the tetrads; C, the young tetrads arranging 

 themselves on the first polar body spindle; D, tetrads in first body spindle; E, 

 separation of the dyads in the same; F, position of the dyads in the second polar 

 body spindle, the first polar body being really above the margin of the egg. (After 

 Riickert.) 



