1920] Taylor: Neuromotor Apparatus in Euplotes 409 



which is not the case. Furthermore, the organelles with which the 

 strands are associated are never translated in "the direction of the 

 strands leaving the motorhvm, but rather in a direction at right angles 

 to the course of the fibers, thus militating against a contractile func- 

 tion for the fibers" (Sharp, 1914, p. 86). 



The perfect coordination in the activity of mobile parts, all of 

 which are supplied by strands from the centrally placed motorium, 

 and the advantageous location of the system to function "as a center 

 of motor coordination in an animal which is exceedingly active, exceed- 

 ingly responsive to external stimuli and one, moreover, which exhibits 

 a high degree of selective feeding." are phenomena which could be 

 most satisfactorily explained on the hypothesis that this apparatus 

 functions as a primitive type of nervous system whose coordination 

 is effected through the central motor mass, the motorium. Accord- 

 ingly, Sharp gave to this system the name "neuromotor apparatus." 



In a fresh-water ciliate. Euplotes patella, a fibrillar system com- 

 parable with that of Diplodinium ecaudatum has recently been worked 

 out and described by Yocom (1918). It is noteworthy that these two 

 forms are of different orders and habitats as well, the latter an Oligo- 

 triehan parasite common in the stomach of ruminants, while the former 

 is free-living and a member of the order Hypotricha. The presence of 

 these homologous systems in filiates so varied in mode of life and kin- 

 ship indicates the possible widespread occurrence of comparable 

 systems in numerous other forms of this exceedingly interesting and 

 important group of protozoans. 



Let us now consider the nature of this "neuromotor apparatus" in 

 Euplotes patella, as found and described by Dr. Yocom. Prefacing 

 this consideration, it will be convenient to offer a very brief account 

 of the external form of the animal and the relative positions of its 

 ectoplasmic organelles. The body in general contour roughly resembles 

 the bowl of a tablespoon, the convex surface of which represents the 

 dorsal side of the organism, and the concave surface its ventral side. 

 For the anterior end, to complete the figure, one should picture a mere 

 stub of a very broad handle still attached and well rounded to suit the 

 contour of the bowl. The stub would then represent the oral lip of the 

 animal. This lip forms an anterior projection of the dorsal side over 

 a wide triangular cytostome at whose posterior apex is the pharynx 

 situated on the left about halfway down the body. A series of mem- 

 branelles borders the dorso-posterior margin of the oral lip and on the 

 left turns ventrad to continue along the left side of the cytostome into 



