236 THE BIOLOGY OF STENTOR 



creased without much affecting the frequency of beat. The general 

 picture, then, is not of a row of effectors joined by one connecting 

 nerve or neuroid process, but of a series of triggers which fire each 

 other in succession. 



CiUu-m of 

 mem br.anelle 



ciliary roots ot 

 2)asBl lamella 



bsLSaL 

 fiber 



Fig. 68. 



Diagram of a theory of metachronal coordination. 

 (After Sleigh, 1957.) 



This would leave the basal fiber without defined function, and 

 Sleigh does not even mention it. Apparently he regards the conduc- 

 tion as simply spreading through the ectoplasm between the 

 membranelles. That such transmission without fibrous connections 

 is possible even at much wider dimensions is indicated by the 

 membranellar response of grafted stentors. Immediately after many 

 stentors were grafted together, and even if the membranellar bands 

 are cut into sections of various lengths, all the membranelles in the 

 mass were observed to stop and start together as the cilia simul- 

 taneously reversed or beat " forward ", long before any intimate 

 structural reconnections could have been made, as if a coordinating 



