CHAPTER U 



Genetic Continuity of Kineties 



and the Problems of Isolated Populations 



of Kinetosomes 



The complicated series of events we have described poses 

 two important problems: (1) Why do kinetosomes some- 

 times behave differently in different sectors of one kinety? 

 (2) Why do different ciliary rows behave differently? 



Let us consider first the rows 8 and 9. Their posterior 

 part is simple like the other rows. The median part has 

 disappeared, kinetodesma as well as kinetosomes. The 

 kinetosomes of the anterior part have divided, once in the 

 row 8 and twice in the row 9 (see Fig. 3b, p. 13). 



It is perhaps necessary to point out that all kinetosomes 

 of one kinety are equivalent. During division, the median 

 kinetosomes become located either on the posterior part of 

 the '^proter" or on the anterior part of the ^'opisthe"; the 

 proter is the anterior daughter ciliate, the opisthe the pos- 

 terior one. It is therefore obvious that the fate of the 

 kinetosomes of one kinety depends on its position on the 

 ciliate. This means that the behavior of the kinetosomes, 

 the facts that they remain without apparent change, that 

 they disappear, that they multiply, depend on the prop- 

 erties of the underlying cytoplasm. The cytoplasm may 

 be "neutral." It may produce the disappearance of the 

 kinetosome or induce its multiplication. Properties of the 

 cytoplasm vary in the anterior, median, and posterior parts 



of the kinety in the most conspicuous way. 



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