68 MORPHOGENESIS IN CILIATES 



From the evolutionary point of view, it is worth noticing 

 that the ciliated phase is phylogenetically the primitive one. 

 The production of the ^'embryo," characterized by the or- 

 ganization of the anarchic superficial network into a regular 

 pattern, the lining up of kinetosomes, and the production 

 of cilia, corresponds to the transitory return to a primitive 

 condition, or, better, to the cyclical reappearance of some of 

 the features of Podophrya's ancestor. 



The structures which develop before division, either in 

 the parent as a whole or only in the embryo or opisthe, are 

 characteristic of a phylogenetically primitive condition. 



