CILIATE FIBRILLAR SYSTEMS 



203 



Neresheimer's means of observing a "three-fold increase" in the thick- 

 ness of the contracted myonemes. 



Perhaps the most complete structural analysis of the fibrillar differ- 

 entiations of S. coeruleus is that by Dierks (1926). His work, which 

 was carried out in Korschelt's laboratory, considerably revised and 

 extended earlier accounts of the fibrillar system of this heterotrich. 



He noted a gradual thickening of the myonemes from the peristome 

 border down to the aboral pole, where the fibers do not end abruptly, 



Figure 73. Connecting 

 branch from neuroid to 

 myoneme in Stentor. 

 (Dierks, 1926.) 

 myo. str. — striation of myo- 

 neme 

 neu. — neuroid 

 neu. br. — neuroid branch to 

 myoneme 



neu. — 



..neu. dr. 

 _ _ myo. sir. 



as Johnson (1893) thought, but bend sharply inward and revert an- 

 teriorly to form a pencil-like bundle (see also Schr5der, 1906a). This 

 bundle soon becomes fimbriated, its component fibrils branch, and their 

 tapering ends disappear in the cytoplasm "near the center of the con- 

 tracted animal." 



Dierks confirmed Neresheimer's (1903) findings of a second fibril 

 coursing parallel and usually peripheral to the myoneme, both of which 

 also stained differentially by Mallory's method. But the relationship of 

 these two sorts of fibrils was found by Dierks to be evidently more 

 intimate than Neresheimer had observed. In various sectioned and 

 stained preparations, the smaller fibril, or "neuroid," gave off one or 



