CILIATE FIBRILLAR SYSTEMS 219 



would definitely suggest a conductive function for his neuroids. He saw, 

 in several preparations, that the smaller fibril gave off one or more 

 branches to its adjacent myoneme. As will be noted further on, this claim 

 has recently been challenged by von Gelei (1929b). 



Another fibril, found and described by Schuberg (1890), connected 

 the basal lamellae of the entire series of membranelles. This basal fibril 

 was noted also by Johnson (1893), Maier (1903), and Schroder 

 (1906), but Neresheimer and Dierks maintain that such does not exist. 

 Dierks (1926) does describe a fibril coursing along the platelets of the 

 membranelles, which he thinks both Schuberg (1890) and Meyer 

 (1920) may have seen but misinterpreted. 



The evidence supporting the interpretation that the myonemes are 

 contractile organelles has been supplied from many sources, beginning 

 with their discoverer, Lieberkiihn (1857). Ehrenberg (1838) claimed 

 to have seen in a living Stentor that in the extended state the myonemes 

 were serpentine, while with the contraction of the body they became 

 shortened and straight. But since he misidentified the pigmented meridi- 

 ans as myonemes, the significance of his observation is uncertain. 



Probably the most significant evidence for the contractile nature of 

 Stentor' 5 myonemes was provided by Johnson (1893) and verified by 

 Dierks (1926) . The former investigator compressed the living organism 

 beneath the cover slip and could then observe the myonemes "alter- 

 nately to extend and contract," concluding that "no one who has once 

 observed them under these conditions can doubt that they are responsible 

 for the contractions of the animals." Biitschli (1889) apparently made 

 similar observations on living Stentor upon applying an electric stimulus. 

 Merton (1932) has confirmed these former evidences of the contractile 

 properties of Stentor' s myonemes. 



Dierks (1926) states further that "these fibrils are definitely shorter 

 and thicker in the contracted animal and longer and shorter" when the 

 organism is extended. He also noted, however, that this behavior was 

 lacking in the myonemes toward the posterior end of the body, and 

 supposed that here the body protoplasm contracted more or less inde- 

 pendently, suggesting a progressive differentiation in the myonemes 

 anteriorly along their course. 



The assigned contractile function of the myonemes of Stentor appears 

 to be agreed upon without exception. Schroder (1906) added to the 



