1920] Taylor: Ni uromotor Apparatus in Ewplotes 411 



conspicuous "lattice-work structure" whose bases, like those of the 

 membranelles, very closely approximate the cytostomal fiber. Thus is 

 formed (Yocom, 1918) "an unbroken fibrillar complex between the 

 heavy anal cirri which are used chiefly in locomotion and the mem- 

 branelles of the adoral zone which function as organs of food getting, 

 organs of locomotion, and as tactile structures. " Several finer and 

 shorter fibers pass out from the base of each of the other thirteen cirri 

 but Yocom found no indication that these fibers connect with any part 

 of the complex uniting the membranelles, the lattice-work structure 

 of the oral lip, and the anal cirri. 



The anatomical continuity of this fibrillar system, its selective stain- 

 ing properties, the anterior, free position of the motorium and the 

 intimacy of its several branches with the large, vigorous anal cirri, 

 with the peculiar diffused lattice-work of the oral lip and with the ever 

 active membranelles, these were significant features which strongly 

 suggested that the whole, unique arrangement must have a function 

 more highly specialized than merely that of support or even one of 

 contractility. Rather, the system here, as the one in Diplodinium 

 ecaudatum, should be regarded as possessing properties of conductivity 

 functioning to coordinate the movements of the organs with which it 

 is associated. It, accordingly, was also designated "neuromotor 

 apparatus." 



The morphological evidences which Yocom 's researches have yielded 

 lend strong support to this "neuromotor" hypothesis. Yet, however 

 significant may be the foregoing evidences favoring the function of 

 conductivity for this novel apparatus in Euplotcs, to establish this or 

 any interpretation of organic function, methods beyond the bounds of 

 morphological inquiry must be introduced. In this endeavor, the in- 

 vestigator enters another field of labor, viz., that of experimental 

 biology, the need and importance of which has, in comparatively recent 

 years, become more fully recognized among biologists. Phenomena 

 studied and described by the morphologists are of primary importance. 

 A comprehensive knowledge of a structure and its relations is pre- 

 requisite to an understanding of its function. But functions can not 

 be ascertained by exploring and mapping parts. Experimental means 

 must also be provided, otherwise further progress is impeded and may 

 even be rendered impossible. 



In view of this and because of the important significance that 

 attends the theory of the presence in certain Protozoa of structures 

 which are neural in function, it was thought advisable to undertake 

 the task of which this paper is an account. 



