386 



THE AMEBIC AN NATURALIST [Vol. XLV 



Boveri ('92). The first cleavage division of the egg of 

 Ascaris results in two daughter cells, each containing two 

 long chromosomes (Fig. 1, A). In the second division 

 the chromosomes of one cell divide normally and each 

 daughter cell receives one half of each (Fig. 1, B, s). 

 The chromosomes of the other cell behave differently; 

 the thin middle portion of each breaks up into granules 



(Fig. 1, A) which split, half going to each daughter cell, 

 bul the swollen ends | Pig. 1, B, c) are cast off into the 

 cytoplasm. In the four-cell stage there are consequently 

 two cells with the full amount of chromatin and two with 

 a reduced amount. This inequality in the amount of 

 chromatin results in different sized nuclei (Fig. 1, C) ; 

 those with entire chromosomes (s) are larger than those 

 that have lost the swollen ends (c). In the third division 



