1918] Yocum: The Neuromotor Apparatus of Euplotes Patella 363 



there are other factors which seem far more significant. Chief among 

 these is the intimate relation between the neuromotor apparatus and 

 the motor parts of the animal concerned in locomotion and feeding. 

 Without exception all of the above described structures, that is the 

 fibers, motorium and granules, are more or less closely associated and 

 connected with every part of the animal which has to do with its 

 locomotion or food getting, or both. 



The largest cirri and those capable of the most powerful stroke are 

 the anal cirri, and as we have seen they are connected by heavy fibers 

 to a mass which has been termed the motorium, or as has been sug- 

 gested, a coordinating center. These large cirri move in only one plane 

 but are the chief organs of locomotion while the other cirri move in a 

 whirling motion and are almost constantly lashing about. The fiber 

 in connection with the cytostomal membranelles is also connected with 

 the motorium. This likewise favors the idea that the motorium is a 

 coordinating center and that the fibers connected with it are of nervous 

 character, for the phenomenon of food getting must in these forms be 

 closely associated with the phenomenon of locomotion, since the food 

 is largely made up of free, rapid-swimming organisms and not the 

 minute forms that serve as food for the sessile ciliates such as 

 Vorticella. 



In studying Euplotes patella that have been treated with very weak 

 solutions of certain chemicals such as neutral red, methylene blue and 

 especially nicotiue, it has been noticed that the anal cirri and the 

 cytostomal membranelles are the last to cease moving. The other cirri 

 become quiet but the anal cirri and membranelles have been seen to 

 move even after the cytoplasm has begun to break up. Such phenomena 

 favor very strongly the idea that the motorium serves as a coordinating 

 center between the anal cirri and cytostomal membranelles. However, 

 other observations on living animals give even stronger evidence in 

 favor of the neural function. It has also been noticed in specimens 

 that have been subjected to a very weak solution of nicotine that the 

 frontal, ventral and marginal cirri continue moving even after the 

 animal has ceased to swim about. The membranelles also move but 

 more slowly than in normal animals. Occasionally one or more of the 

 anal cirri may be seen to make a feeble movement not sufficiently 

 strong to cause the animal to move. However as the animal revives 

 from the effects of the narcotic and begins to swim about by vigorous 

 kicks of the anal cirri, a decided increase in the rate of movement of 

 the membranelles may be noticed. Such an increase continues as long 



