EP^FECTS OF CARBON DIOXIDE ON EGGS 



375 



The observations recorded above, have a certain bearing on 

 the question, since it is clear from them that genuine fragmenta- 

 tion may take place in the chromosomes of Ascaris megalocephala, 

 in some cases all four chromosomes being affected. The fragmen- 

 tation of the chromatin in figure L, however, certainly has noth- 

 ing to do with the accessory chromosome, and since a series may 

 be formed in which one, two, or even all four chromosomes may 

 be broken up, it becomes a question whether or not we can in- 

 terpret such cases as shown in figures K, M, or N, as having any 

 relation to the accessory chromosome. Just what relation 

 the fragmentation in the normal eggs has to do with that ob- 

 served in the eggs treated with CO2, is uncertain, but it does not 



Text figures O and P 



seem improbable that they are both expressions of a tendency 

 residing in the chromosomes. 



A second anomaly found is shown in figures and P. In 

 figure O, the P2 and EMSt cells are both dividing, and it will be 

 seen that both are undergoing diminution. It is especially to 

 be noted that the spindles of the two cells are not parallel. In 

 figure P, another egg is shown in which both the P2 and EMSt 

 cells are undergoing diminution. A detailed drawing of the two 

 cells is seen to one side. It is especially to be noted that a proto- 

 plasmic ball lies on one of the two cells. 



In figure 16 is shown a rare case where the Po and EMSt cells 

 are fusing after division. Note particularly the protoplasmic 

 ball coming from the fusing cells. (The Si cell is seen lying be- 



