1918] Yocum: The Neuromotor Apparatus of Euplotes Patella 359 



connection with the anal cirri, I have never been able to see and feel 

 sure that such is not to be found in Euplotes patella. Griffin (1910) 

 found this dissociated system of fibers in E. worcesteri, but pictures 

 fewer fibers than are present in E. patella. 



Function of N euromotor Apparatus. — In the preceding paragraphs 

 attention has been directed almost exclusively to a description of the 

 anatomical relationships of the neuromotor apparatus, which has been 

 divided into two parts, the associated or coordinating part and the 

 dissociated part joined to certain irregularly moving cirri. In the 

 succeeding paragraphs this neuromotor apparatus will be considered 

 .from a functional point of view and the anatomical structures will be 

 considered in their relation to the activities of the organism. 



In the above descriptions of the anatomy of the neuromotor appa- 

 ratus several suggestions have been made indicating the nervous 

 function of the system. In fact the term "neuromotor apparatus" 

 itself predicates this meaning, namely a structure in connection with 

 the motor parts of the organism over which neural impulses may be 

 conveyed. With this meaning in mind it is our purpose to show how 

 the different parts of this system function as a primitive nervous 

 system. 



The motorium which has been defined as a "common center of 

 motor influences" lies in a position whereby it functions as a coordi- 

 nating center between the constantly moving membranelles on the one 

 hand and the heavy, vigorously lashing anal cirri on the other. Six 

 fibers, one of which connects with the cytostomal membranelles and the 

 sensory structure of the anterior lip and the other five heavy long 

 fibers from the anal cirri join the bilobed motor mass, thus permitting 

 of the coordination of the movements of locomotion with the move- 

 ments of the membranelles in food getting, as well as affording a means 

 of coordinating the movements of locomotion in response to sensations 

 received by the anterior cytostomal membranelles and the lattice-work 

 structure in the anterior lip, a region which first of all comes in con- 

 tact with any unfavorable conditions. This function of the motorium 

 will be better understood when we consider the function of the strands 

 or fibers in connection with it. 



By far the most conspicuous of these fibers are the five in connec- 

 tion with the anal cirri. These have been described in an earlier para- 

 graph as heavy granular cords connecting the motor mass anteriorly 

 with the large anal cirri posteriorly. In the bases of these cirri these 

 cords break up into a fan shaped structure of fine fibrils which join to 



