142 David Day Whitney 



Three polar bodies are to be found near the periphery of the egg 

 close to the line of meeting of the blastomeres. One was usually 

 larger than the other two and often at a httle distance away from 

 them (Fig. 4, A-B), although in one instance the three polar bodies 

 were close together and seemed to be of the same size (Fig. 4, C). 



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IS" I? '!iM'^ V. 



Fig. 3 Male parthenogenetic egg. A^ B, equatorial plates of the polar spindle, showing twelve to 

 thirteen chromosomes; C, D, polar spindle in telophase, showing ten to fourteen chromosomes. 



Lauterborn states that in the male parthenogenetic egg of 

 Asplanchna the first of the two polar bodies which was extended 

 usually divided. 



Lenssen concluded that only one polar body was formed because 

 he saw the maturation spindle in the telophase stage. He did not 

 follow the history of the chromosomes in the later stages and conse- 

 quently never saw any polar bodies. 





f / 



B 



Fig. 4 Male parthenogenetic egg. A, B, eggs in the four-cell stage, showing three polar bodies, 

 two of which are smaller than the other; C, egg in the two-cell stage, showing three polar bodies of 

 nearly the same size. 



V WINTER EGG 



The fertilized or winter egg has a very thick envelope. An 

 oval shaped small body which is probably the sperm nucleus is 

 always found near the egg nucleus. 



The chromosomes were seen in sections on the maturation spindle 

 (side view) in all stages but in only two anaphase stages (Fig. 5, 



