352 University of CaJifornia Publications in Zoology [Vol. 20 



3. The cilia arise in longitudinal grooves in the pellicle. These 

 grooves are slightly oblique on the oral side and meet in the ciliary 

 suture, a line that runs obliquelj' through the oral surface from the 

 anterior to the posterior end. 



4. The neuromotor system consists of two peripheral whorls of 

 fibers, the larger on the oral side, the smaller on the aboral side, and 

 of two other groups, the cytopharyngeal fibers, one running to the 

 anterior zone of membranelles in the eytopharynx, the other around 

 the margin of the cytostome to the posterior membranelle zone. 

 This zone has not been previously described. AH the fibers of the 

 peripheral whorls and of the eytopharynx ramify out from the 

 neuromotor center at the anterior end of the cytostome. 



5. This is a body at the anterior end of the cytostome correspond- 

 ing to the motorium of other ciliates. This body is differentiated with 

 difficulty. 



6. The old cytostome and eytopharynx and, so far as is known, 

 the neuromotor system also, are dedifferentiated prior to division. 

 The cytostome, eytopharynx, and neuromotor fibers of the anterior 

 daughter are new structures. The exfent to which dedifferentiation 

 and redifferentiation occur has not been determined. 



7. The neuromotor system of Paramaecium is of a generalized 

 type in conformity with the lack of specialization of parts in the 

 organism. 



8. Griibler's methylene blue, when injected into the animals, did 

 not stain the neuromotor fibers. 



9. The axial gradient in Paramaecium could not be fully deter- 

 mined because the animals did not disintegrate. There is, however, 

 an anterio-posterior gradient in cessation of ciliary action along the 

 longitudinal axis which would be expected if the fibrillar system is 

 interpreted as eonductile. 



10. A distinct interruption of coordinated movements is effected 

 when the region of the neuromotor center is injured. Cutting the 

 cytopharyngeal fibers interrujjted the coordination of movement 

 between the membranelles anterior to the cut and those posterior to it. 



11. The morphological as well as the experimental studies indicate 

 that the fibrillar system of Paramaecium is eonductile in function. 



