1918] Yocum: The Neuromotor Apparatus of Euplotes Patella 377 



point of contact ; a third possibility exists that they may differentiate 

 independently out of the ectoplasm like the other parts of the system 

 and then become connected with the fibers from the cirri and mem- 

 branelles. The second possibility seems to be the most plausible. The 

 fibers are always connected with the motorium in a definite way, those 

 from the anal cirri converging to the inner end of the motorium while 

 that one from the membranelles always connects to the right hand 

 end. This could be easily explained by supposing that the fiber from 

 the membranelles continued its growth toward the right and carried 

 the granules on beyond the point of convergence of the five fibers from 

 the anal cirri. The fact that the fiber is continued on beyond the 

 point where the membranelles and sensory structures develop is evi- 

 dence in favor of such a conclusion, even though the process of growth 

 has not been clearly seen, due to the phj^siological condition of the 

 animal. By an increase in the number of granules the motorium 

 attains its normal size. 



It has thus been shown that the whole neuromotor apparatus and 

 the motor organs are derived from the ectoplasm and that their first 

 indication is a pitting in of the outer surface of the pellicle. This is 

 quite significant in as much as it is always the ectoplasm that initiates 

 the separation of two cells. We may carry our analogy still a step 

 further and suggest the great similarity between the division process 

 in these organisms, and the same process in all ]\Ietazoa which re- 

 produce asexually in which the ectoderm is the most active in the 

 separation of the organisms. Such a parallel indicates that the 

 ectoderm is important in this regard and probably more closely related 

 to the process of reproduction, especially asexual reproduction, than 

 we usually think. Such an analagy may be still more closely con- 

 firmed if we say that the multinuclear condition as found in ciliates 

 denotes a multicellular condition rather than that of unicellularity, 

 thus making the ciliates more nearly like Metazoa with their cell 

 divisions. Thus the analogy between ectoderm and ectoplasm is more 

 apparent. At least we see from this study of Euplotes that the 

 ectoplasm is of much more importance than a mere covering. 



