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(i K HM- < EL L I)E TEH MIX. 1 XTS 



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one of the two cells with the two entire chromosomes 

 loses the swollen ends of each; the other (Fig. 1, D, s) 

 retains its chromosomes intact. A similar reduction in 

 the amount of chromatin takes place in the fourth and 

 fifth divisions and then ceases. The single cell in the 

 thirty-two-cell stage which contains the full amount of 

 chromatin has a larger nucleus than the other thirty-one 

 cells and gives rise to all of the germ cell, whereas the 

 other cells are for the production of somatic cells only. 



The primordial germ cell of Ascaris, therefore, con- 

 tains two entire chromosomes ; every other cell possesses 

 two chromosomes which have lost part of their substance. 

 In other words, the germ cells possess a certain amount 

 of chromatic material not present in the somatic cells. 



There is also an early differentiation of the germ cells 

 in the fresh water crustacean. Cyclops (Ilaecker, '97). 

 According to Haecker, " Aussenkornchen" arise at one 

 Pole of the first cleavage spindle (Fig. 2, A, ah) ; these 



