366 University of California Publications in Zoology [Vol. 18 



an argument for Euplotes patella. It seems quite as adequate for the 

 latter as it did for the organism for which it was written. 



Neither can we see any way in which this neuromotor apparatus 

 may serve as a supporting structure. Its shape is not such that it 

 would be advantageous as a skeletal organelle; neither is it large 

 enough to serve as a firm attachment for contractile fibers. The 

 pellicle, which is quite thick, can serve as a means of support. In fact 

 the pellicle is of such a character that the shape of the body is kept 

 constant and permits of little or no bending. 



The only part of fhe whole neuromotor apparatus which might in 

 any way serve as a skeletal organ is the lattice-work structure in the 

 anterior lip. However, it seems that sufficient evidence has been 

 advanced to show that it serves as a sensory organelle, whose function 

 it is to receive sensations caused by stimuli at the anterior end. Then 

 too, the lip is so thin that no skeletal structure is needed aside from 

 the rigid pellicle on both dorsal and ventral sides. 



In his description of the neuromotor apparatus of Diplodinium 

 ecaudatum Sharp (1913) describes a number of fibers in connection 

 with the neuromotor apparatus which extend into the cytoplasm and 

 end near the micronucleus. From the work on the soil amoeba, 

 Naegleria gruheri ("Wilson, 1916), and certain of the flagellates, such as 

 Polymastix (Swezy, 1916), Trichomonas (Kofoid and Swezy. 1915). 

 and Giardia (Kofoid and Christiansen, 1915), it has been shown that 

 the motor organs are connected with the nucleus by a rhizoplast and 

 are probably controlled by it. This relationship will be more fully 

 discussed in later paragraphs in which a comparison of the neuro- 

 motor apparatus of flagellates and ciliates is taken up. However, this 

 relation of the motor organs and nucleus in flagellates and the indi- 

 cation of such a relationship in Diplodinium suggests a possible struc- 

 tural relationship in other forms. In Euplotes patella there is no 

 indication of a connection between the neuromotor apparatus and either 

 the micronucleus or macronucleus. The motorium is on the opposite 

 side of the animal from the micronucleus. At division the micro- 

 nucleus migrates from its position during the vegetative stage to the 

 left of the macronucleus, where it undergoes mitosis. The two halves 

 separate, one remaining in the anterior end to become the micro- 

 nucleus of the anterior daughter, while the other migrates posteriorly 

 to become the micronucleus of the posterior daughter. "While this is 

 occurring there is no indication of any change in position of any part 

 of the neuromotor apparatus. It would seem that if the neuromotor 



