1919] Kofoid-Swczjj: Trichoiiympha campanula 5!) 



GENERAL DISCUSSION 



Tlie entire absence of a eytostome in this flagellate has proven a 

 source of some difficulty in explaining its methods of food taking. 

 It is distinctly holozoic in its mode of nutrition, as the abundance 

 of food particles found in the endoplasm testify. These often fill the 

 posterior region and consist of particles of wood and bacteria, and 

 even encysted forms of Trichomitus termitidis. The anterior region 

 of endoplasm has, in all individuals observed, been entirely free from 

 food bodies or vaciioles, with the exception of small, darkly staining 

 rodlets which may be bacteria or possibly chromidia. The particles 

 of wood found in the posterior region of endoplasm are often rela- 

 tively huge and ma}' be contained in a distinct food vacuole, but are 

 usually found lying free in the plasma, without evident vacuoles. 



The method of ingestion of these particles is a complete mystery. 

 Leidy (1881), in his account of these flagellates, called attention to 

 the presence of food bodies and the lack of any visible channel for 

 their entrance into the body. Kent (1884), in his studies on the 

 forms from the Tasmanian ants, decided that there was an oral aper- 

 ture at one side of the body a short distance from the apical extremity. 

 From this he traced a narrow oesophageal tract which opened into the 

 digestive cavity at the posterior region of the body. He further 

 states that in a medium of thinly diluted milk both the pharj-nx and 

 digestive tract were frequently found filled with the milk corpuscles. 



Porter (1897) attempted to confirm these observations of Kent's, 

 botli in the living animals and by means of sections of the body, but 

 was unable to find any trace of an oral aperture. He does, however, 

 offer another solution to this problem, that is, that the food particles 

 are drawn to the posterior part of the bodj^ by the cilia and there 

 ingested through the thin pellicle. Unfortunately the evidences for 

 this are unconvincing. 



Other investigators working on these forms, e.g. Hartmann and 

 Grassi, have been equally unsuccessful in solving this mystery, nor 

 has our own work afforded any light upon the subject. It is mani- 

 festly impossible to consider that food may be taken in at any point 

 of the surface covered by the highly differentiated ectoplasm possessed 

 by this flagellate. That the food is taken in at the extreme posterior 

 portion of the body seems to be in direct contradiction to all known 

 methods of feeding among Protozoa or elsewhere. There remains, 

 then, the anterior end of the body to consider. 



