ANALYSIS OF STENTOR 



237 



influence passed like a flash over the entire surface of the mass 

 (Tartar, 1954). Myonemes respond similarly, components of a 

 fusion mass contracting together almost from the moment of 

 grafting (Weisz, 1951a). 



One approach to analyzing what the functions of fibrous 

 structures associated with the membranelles may be is provided 

 by the selective resorption of parts of bands during fusion of heads 

 in grafted stentors. In the specimen shown in Fig. 69 the resorbing 

 membranelles first lost their metachronal rhythm, beating irregu- 

 larly in a local area. This is as if structures responsible for this 



Fig. 69. Loss of coordination in membranelles anticipating 

 resorption of portions of the membranellar band. The ends of 

 the two peristomes which were resorbed in a doublet stentor to 

 fuse the frontal fields first showed independent beating of 

 membranelles. 



type of coordination were the first to become dediflFerentiated, for 

 the ectoplasm presumably retained its continuity. 



Other responses of the membranelles to chemical treatments 

 have been observed (Tartar, 1957a). In solutions of 1% Nal the 

 membranelles remained continuously stopped, but in CaCl2 they 

 kept beating vigorously until the organelles were destroyed. 

 Ethanol stimulated the membranelles to keep beating even while 

 the remainder of the cell was being destroyed, confirming the 

 earlier observation of Daniel (1909). This activity was in marked 

 contrast to the normal avoiding response in which the membra- 

 nelles are stopped. In MgCl2, at much higher concentrations than 

 used by Sleigh, the membranelles continually started and stopped 



