244 CILIATE FIBRILLAR SYSTEMS 



Ptychostonium chattoni Rossolimo (Studitsky, 1932).- — The mouth of 

 this parasitic ciiiate is at its posterior end. At the anterior end is a horse- 

 shoe-shaped sucker with a projecting rim for attachment. 



The sucker [Fixationsapparat) is provided with a system of fibrils. 

 The largest fibril, the peripheral cord, borders the sucker and gives off 

 at its ends fine fibrils that extend into the cytoplasm. The sucker's disc 

 has four sets of fibrils: ( 1 ) the deeper set comprises two groups of paral- 

 lel fibrils that cross each other at a sharp angle as they traverse the disc, 

 both groups coming to adhere to the peripheral cord; (2) the uppermost 

 set, visible in the living organism, courses from right to left and from 

 anterior to posterior; (3) a third set of fine fibrils are attached to the 

 peripheral cord by their anterior ends; and (4) the fourth set, com- 

 posed of sixteen or seventeen strands that run from right to left and 

 from anterior to posterior, frays into four or five fine fibrils at the anterior 

 end of each strand, to become attached to the peripheral cord and to 

 other adjacent fibrils; the posterior ends of these strands become fimbri- 

 ated also into fine fibrils. All apparently serve for support. 



Methods 



Fixatives: Schaudinn's, Carney's, Bouin's, Champy's and Benda's (for 



whole mounts), Altmann-Kull's (for sections). 

 Stains: Heidenhain's haematoxylin, safranin, von Gelei's toluidin blue, 



Mallory's triple. 



B. HETEROTRICHA 



Balantidium coli Malmsten and B. suis sp. nov. (McDonald, 1922) . — 

 The motortum of Balantidium suis lies within the ectoplasm of the 

 apical cone, close to the right ventral wall of the esophagus. A fibril 

 encircling the esophagus arises and ends at the anterior end of the moto- 

 rium, where the adoral ciliary fiber also arises. The circuniesophageal 

 fibril has irregular enlargements, from which fibers pass both posteriorly 

 and anteriorly into the ectoplasmic mass of the anterior end. These fibrils 

 appear to fade out in the ectoplasm. The adoral fiber connects the basal 

 granules of the adoral cilia. The remainder of the fibrils are not directly 

 connected with the motorium. 



The basal granules of the peripheral longitudinal spiral rows of cilia 

 are so closely set that it has been impossible to see a fibrillar connection. 

 No transverse fibrils connecting the rows were observed. A ciliary rootlet 



