202 CILIATE FIBRILLAR SYSTEMS 



and critical and, for the most part, they have remained vahd. Reference 

 now may be made to his search for the so-called myoneme canal, de- 

 scribed by Butschh and Schewiakoff (1889, p. 1297). 



Beneath the "Zwischenstreifen" they found a fairly spacious fluid- 

 filled canal which surrounded the myoneme throughout its course. 

 Johnson looked in vain for this canal, finally deciding that he was 

 "unable to find the least evidence of such a structure, either in optical 

 or actual sections." The majority of authors — including Delage and 

 Herouard (1896), Maier (1903), Neresheimer (1903), and especially 

 Dierks (1926) — agree with Johnson that the canal does not exist except 

 as an artefact. Schroder (1907), on the contrary, affirms its form to be 

 oval or circular in cross-section, its shape and position varying with the 

 degree of body constriction. Roskin (1918) and von Gelei (1929) 

 claim also to have definitely identified it. The latter regards it as an 

 ""organic part" of the myoneme, '"solid and elastic." 



Neresheimer's chief contribution to the microanatomy of Stentor was 

 his discovery of another complex of fibrils to which he gave the name 

 "Neurophanen." These were associated contiguously with the myonemes, 

 but coursed usually peripheral to them. In suitable preparations which 

 had been diflferentiated with Mallory's triple stain, the myonemes were 

 distinctly red, whereas the neurophanes were colored a dark violet. The 

 Zwischenstreifen remained unstained. Schroder (1906) maintained that 

 these fibrils were rather only a structural feature of the "Zwischen- 

 streifen," which, according to his results, also with Mallory's stain, did 

 show an intense purple color. More recently, however, von Gelei (1925) 

 and Dierks (1926) have identified similar fibrils, as will be noted 

 further on. 



Neresheimer traced these neurophanes as coursing, each fibril directly 

 over a myoneme, from the aboral plate to about halfway up the body. 

 Here some ended in a knob and all others disappeared before reaching 

 the peristome border. While the myonemes became shorter and thicker 

 in fully contracted Stentors, the neurophanes appeared sinuous but 

 otherwise remained unchanged. It is not clear, however, how Neres- 

 heimer could make sure of the changed or unchanged appearance of 

 these fibrils, since he stated that he was not able to fix Stentor in an 

 uncontracted state. Evidently the myonemes may be visible in the living 

 organism (Biitschli, 1889; Johnson, 1893), which may have been 



