82 



Asa Arthur Schaeffer 



perhaps that these should be fully described at this point to avoid 

 the necessity of giving an account of them while discussing the 

 experiments. 



In a normal attached Stentor in a watch glass under a binocular 

 microscope there are observed four groups or systems of cilia by 

 means of which the greater part of the behavior is effected. (See 



Fig. I. Normally extended "hungry '' Stentor. fe c. Body cilia; (i c, discal cilia; /, funnel; m, mem- 

 branella; mo, mouth; n, nucleus; p, pouch. 



Fig. I.) These four systems are: (i) the membranellae, (2) the 

 discal cilia, (3) the cilia of the pouch and funnel, and (4) the 

 general body cilia found on the sides of the Stentor. Each of 

 these sets of cilia has a function quite different from that of any of 

 the other groups, and the extent to which their behavior can be 

 modified also differs among the various groups. 



