CONCLUSIONS 221 



Endoplasmic myonemes or M-bands of Stentor; transverse 

 bands connecting membranelle roots distally. 



Ectoplasmic network and *ectoplasmic band of Njctotherus. 



Innermost cortical layer, esophagus and endoplasmic-sac walls, 

 filamentous tracts in various locations in ophryoscolecids. 



(Tracts and meshworks of filaments near buccal cavity of 

 Etip/otes; these perhaps belong under 2a). 



In addition to all of these there are several examples of probable 

 fibrous connections that are unclassifiable. These include promi- 

 nently the short bridges that interconnect kinetosomes, often at 

 two specific levels, in Eophomonas, Njctotherus, ophryoscolecids, 

 Euplotes, and some other ciliates. 



Now it is clear that in appearance alone one cannot find a 

 consistent fundamental meaning, even if one allows for descriptive 

 errors resulting from imperfect fixation or low resolution. 

 Whereas most of the fibers whose chemical composition has been 

 examined at all appear to be mainly protein, the oral capsule of 

 Gromia is mucopolysaccharide; the fibrils named in category 2a 

 probably have nothing in common. Furthermore, the categories 

 are not mutually exclusive. The ciliary fibrils of the scopulae of 

 peritrichs start out as distinct tubules and may become banded 

 fibrils. The kinetodesmal fibrils of Stentor look striated near their l 

 origin but become distinct tubules upon joining the kinetodesmos. 

 One more property that certainly has fundamental significance 

 may be added to the above listing: fibrils that are known to 

 originate at or to be directly connected with kinetosomes or 

 centrioles are marked with an asterisk (*). Some others, unmarked 

 in the list, are indirectly connected or occur in such positions that 

 connection with kinetosomes/centrioles seems a strong possibility. 



It appears that all of the intracellular fibrils displaying a banded 

 appearance originate at kinetosomes or centrioles. The point of 

 attachment is typically lateral, near the base, but may be terminal. 

 In ciliates thus far studied, the banded kinetodesmal fibril 

 invariably passes parallel to the cell surface, to the right, and 

 anteriad or (only in Stentor and related heterotrichs) posteriad. In 

 flagellates the fibril may pass in any direction from its origin — up 

 toward the cell surface, laterally toward chloroplasts, etc., or 

 medially to and past the nuclear surface. Similarly banded fibers 



