EXTENSIONS 367 



ciliate is achieved. Important among these derived structures is 

 the infracihary network, and Faure-Fremiet (1948a) suggested 

 that this pattern could be viewed as a morphogenetic field, tending 

 to recover from distortions and capable of regaining its equilibrium 

 wholeness following excision of parts. Doublet ciliates are instruc- 

 tive as manifesting doubleness of fields in balance, but any dis- 

 equihbrium between the two sides leads in most ciliates to removal 

 of structural constraint and hence to remodeling of the complex 

 toward the single form. 



According to LwoflF (1950) this cortical network or anisotropic 

 field would tend to become ''saturated" with kinetosomes in 

 certain areas where we observe the organelles. If still more 

 kinetosomes are produced, these would be left free to produce 

 their own field or be guided into a separate field which would 

 become a primordium. 



Although evoking an ectoplasmic pattern on the basis of their 

 orderly arrangement, LwoflP stressed the importance of the kineto- 

 somes in the diflFerentiation of ciliates. This emphasis naturally 

 stemmed from his classical studies with Chatton on the develop- 

 mental cycles of apostomatous ciliates (Chatton and LwoflF, 1935a) 

 indicating a genetic continuity of the kinetosomes and a pluripoten- 

 tiality with respect to what they produce. That is to say, the 

 kinetosomes are self-reproducing and new ones arise only by 

 multiplication of others preexisting; and daughter granules 

 elaborate body cilia, oral cilia, trichites, or trichocysts, etc., 

 depending on how they are determined to develop by their 

 biochemical surroundings or organizing relations with respect to 

 the patterned cortex. That nucleated endoplasmic spheres of 

 stentors entirely bereft of their ectoplasm can regenerate neither 

 the structured ectoplasm nor the feeding organelles (unpublished) 

 also suggests a genetic continuity of kinetosomes, although it 

 cannot be excluded that the morphogenetic failure of these spheres 

 may be due to the absence of normal outer membranes which 

 upsets the entire "metabolism" of the cell. 



Perhaps the best evidence for division of kinetosomes is to be 

 found in the work of Hammond (1937) on Euplotes. At the level 

 of the division furrow the basal bodies of the dorsal bristles were 

 seen to increase in number and this occurred within a lengthening, 

 sub-pellicular tubule which would seem to exclude the migration 



