1918] Yociun: The Neuromotor Apparatus of Euplotes Patella 365 



As was suggested in an early paragraph of the description of the 

 neuromotor apparatus, we are probably dealing with a nervous system 

 of a very primitive sort, a nervous system formed merely by a differ- 

 entiation of protoplasm having the fundamental characteristic of con- 

 ductivity. Since contractility is just as fundamental a property of 

 protoplasm as is conductivity it may be that even in this differentiated 

 portion the two are not entirely separated and that the fibers may act 

 as muscular elements to a slight extent. However, much as we have 

 had this idea in mind in attacking this problem, we have so far failed 

 to find the least evidence that the intra-cytoplasmic fibers of the neuro- 

 motor apparatus as found in Euplotes patella in any way serve as con- 

 tractile structures. 



It may be said by some critics that the fibers in Euplotes described 

 above as a neuromotor apparatus are comparable to the so-called 

 myonemes of other ciliates and that their function must be that of 

 contractility. It seems that sufficient proof has been advanced to do 

 away with such criticism ; it might be suggested here that instead of 

 the neuromotor apparatus being comparable to the myonemes of ciliates 

 and the movement of cilia being due to the contraction of the fibers, 

 the myonemes may be found by further investigation to be comparable 

 to this neuromotor system and that the movement of cilia is due to the 

 contractility of the central axis of each cilium, while the so-called 

 myonemes may be found to be a fiber of a coordinating neuromotor 

 apparatus, or it may be found to have both a neural and a muscular 

 function combined at least in some of the less complex ciliates. 



The motorium in Euplotes patella is quite comparable with that 

 found in Diplodinium and the argument advanced against its having 

 a motor function in the latter animal seems well set forth by Dr. Sharp : 



The shape, size, position, and absence of direct connections with surrounding- 

 structures make the possibility of the motorium functioning as an organ either 

 of contraction or of support seem highly improbable. For in order to function 

 as an organ of contraction it would necessarily need to have as its attachments 

 on the one hand structures which are fixed, and on the other structures which 

 are movable, or it would need to be located between two structures both of 

 which were to be moved. This, however, is not the case, for the motorium 

 seems to have no direct connections with the fixed structures of the body .... 

 (1913, p. 86). 



The motorium (mot., pi. 14. fig. 5) of Euplotes lies free in the cyto- 

 plasm with no evident connection between it and the pellicle, which 

 is the only firm structure of the body. We can ^dd nothing to the 

 argument quoted from Sharp for Diplodinium to increase its force as 



