1918] Yocum: The Neuromotor Apparatus of Euplotes Patella 361 



receiving stimuli. Such impulses received cause a contraction of the 

 central contractile axis of each component cilium of the cirrus, thus 

 causing a lashing of the whole organ. Such an idea is very much in 

 opposition to the view held by Maier (1903), who considers the func- 

 tion of the whole basal plate to be a support by which the cirrus is 

 held firmly in the less dense ectoplasm. The fact that the granules are 

 packed together into a dense plate might in itself be an argument that 

 the plate serves as a support for the cirrus, but even that leaves the 

 question of the function of the individual granules open for solution, 

 and it seems reasonable after considering the anatomical relationship 

 of the structure to attribute to the fibers and granules the function 

 suggested above. 



A similar function is also attributed to the single fiber connecting 

 the motorium and membranelles. This fiber is connected to the inner 

 ends of the rows of basal granules of the membranelles, and although 

 I have been unable to discover a fibrous connection between the fiber 

 and the basal granules as in the case of the anal cirri, the close juxta- 

 position of the granules and their surrounding protoplasm forms a 

 continuous path for impulses which may pass over the fiber to the 

 membranelles. Thus there is a condition not unlike that of the cirri, 

 a granular fiber connecting the basal granules of the membranelle to 

 motorium, the fiber to serve as a path for impulses from the motorium, 

 while the basal granules are that part of the motor organelle especially 

 adapted to receiving them. 



Connecting with this membranelle fiber is the lattice-work struc- 

 ture of the anterior lip. As suggested in an earlier paragraph all 

 evidence is lacking to suggest that this structure serves as a skeletal or 

 muscular element. In fact its position with its many points extending 

 out into the lip and its structural connection with the membranelles 

 and the membranelle fiber strongly suggest a sensory function for 

 this peculiar structure. We must undoubtedly attribute some sensory 

 function to the anterior cytostomal membranelles, but observations 

 show that these organs are active agents in swimming and are probably 

 to be considered as having no greater sensory function than the mem- 

 branelles along the left side of the cytostome. It is evident from 

 watching the animals swimming about that they are very sensitive at 

 the anterior end, and if the membranelles are considered as locomotor 

 rather than sensory organs then the organ which is most closely asso- 

 ciated with them is the lattice-like structure of the lip, which with its 

 points extending well toward the anterior edge of the lip, is in position 



