288 University of California Publications in Zoology [ V O L - 20 



DISCUSSION 



Up to the present time systems of intracytoplasmic fibers and 

 accessory neuromotor masses comparable to that found in Balantidium 

 coli have been fully described in several flagellates and a few ciliates. 

 The very primitive type occurring in Naegleria gruberi (Schardinger) 

 has been described by Wilson (1916). Kofoid (1916) and Swezy 

 (1916) have made a critical comparative study of the motor systems 

 of those flagellates, in which the} 7 have been most carefully studied. 

 That there is a striking similarity in the neuromotor systems of flagel- 

 lates and ciliates is clearly pointed out by Yocom (1918). 



Among the ciliates, intracytoplasmic fibers have been known for 

 some time and there have been several descriptions of them and several 

 conflicting views as to their function (Engelmann, 1880; Biitschli, 

 1889; Schuberg, 1891; Maier, 1903; Prowazek, 1903; Griffin, 1910; 

 Braune, 1913). Sharp (1914), however, was the first to describe fully 

 a completely integrated fibrillar system with a central neuromotor 

 mass, to which he applied the term neuromotor apparatus. 



Of the neuromotor apparatus of ciliates that of Balantidium coli 

 is the third to be quite fully worked out. In 1914 Sharp described 

 the neuromotor apparatus of Diplodinium ecaudatum (Fiorentini). 

 This apparatus consists of six parts. The central motor mass, or 

 motorium, lies in the area of thickened ectoplasm at the anterior end 

 of the animal between the dorsal and adoral membranelle zones. A 

 fiber connects the motorium with the basal granules of the dorsal mem- 

 branelles, a branch from which runs along the base of the inner dorsal 

 lip. Another fiber connects the motorium with the basal granules of 

 the adoral membranelles. A set of opercular fibers leave the motorium 

 and pass along underneath the operculum. Lastly, the motorium has 

 a definite connection by means of a fiber with what Sharp called the 

 circumoesophageal ring. There is also a set of fibers in the wall of 

 the oesophagus, which he termed the oesophageal fibers, and which 

 he believed took their origin from the circumoesophageal ring. All of 

 these structures as well as the micronucleus Sharp found had an 

 affinity for the acid fuchsin when Mallory's connective tissue stain 

 was used. 



In Euplotes patella (0. F. Miiller) the neuromotor apparatus, as 

 described by Yocom (1918), is made up of five distinct parts. The 



