20 MORPHOGENESIS IN CILIATES 



really seen under the microscope. It is obvious that each 

 trichocyst is generated by one granule and that this granule 

 results from the division of a kinetosome. Here, we are 

 faced with an important phenomenon. The kinetosome has 

 not only the properties of growth, division, and the produc- 

 tion of cilia. It has also other possibilities or. as embryolo- 



Fig. 7. Formation of trichocysts and trichites. (1) Gymnodinioides: 



(a) The normal ciliary row. Kinetosomes c and satellite corpuscles s. 

 The kinetodesma is at the right of the kinetosomes (desmodexy). 



(b) Division of the kinetosomes; trichocystosomes are produced, (c) 

 Formation of trichocysts in Gymnodinioides. (2) Formation of tricho- 

 cysts in Polyspira. (3) Formation of trichites in Foettingeria. 



gists would say, prospective potencies. A cilium-bearing 

 kinetosome may, under certain circumstances, divide and 

 give rise to a new granule which will not produce cilia but 

 trichocysts. A granule never produces a cilium and a tricho- 

 cyst. It produces either a cilium or a trichocyst. 



We have reached the conclusion that kinetosomes may 

 divide and produce cilia. We see that the ultimate phase 

 of tomitogenesis reveals a new potency of the kinetosome. 



Let us now recall the conclusions arising from the study 

 of Gymnodinioides. Growth, division of the kinetosomes, 

 production of cilia, production of trichocysts depend on the 

 position of the granules on the ciliate and on the phase of 

 the life cycle. And it is perfectly clear that the "position" 

 or the "phase" is not a metaphysical property. It is obvious 

 that growth, division, and metabolism of kinetosomes, as 

 revealed by the production of cilia or trichocysts, depend on 

 the properties of their environment. 



