1919] Kofoid-Swczy: TricJuinympha campanula 61 



are completely filled by the wealth of fibrils which crowd this part 

 of the ectoplasm. In no case, however, have the lines bordering the 

 different layers of the ectoplasm, which here is unusually thick, been 

 found to be broken, or otherwise to present any indications of a con- 

 striction in the surface of the bodj' at this place. Were this the case, 

 flexions of the head or cone, such as are common in many individuals 

 on every slide, would betray the lack of continuity on one side at least, 

 and no instance of this has been observed, though tlie flagellates 

 have been thrown into every conceivable attitude in making smear 

 preparations. The surface lines or ridges on the cone also seem to 

 be continuous with those of the body without a break in their con- 

 tinuity. We find no evidence of an anterolateral cytostome. 



What purpose this circular vacuole may subserve, finds no 

 explanation in observations we have been able to make. It is almost 

 or (juite obliterated in many individuals and always disappears at 

 the time of division. Its conspicuousness when present in stained 

 material, with its complete lack of structural differentiation in the 

 midst of a highly differentiated zone, would suggest that it is a fluid- 

 filled vacuole of non-stainable substance but gives no further aid in 

 explaining it. That it might function as a cytostome seems impossible. 



Evidences of the complex ectoplasmic and neuromotor structures 

 which we have described above, are to be found in the figures of 

 Porter (1897) for Trichonympha agilis, and in those of Hartmann 

 (1910) for two, at least, of the species he assigns to T. hertwigi. In 

 the former the alveolar zone of ectoplasm with the surface ridges, 

 and something of the fibrillar system with its centroblepharoplast, are 

 shown. In two species which Hartmann has figui'ed, the centro- 

 blepharoplast and suggestions of the complex of myonemes maj' be 

 found. The complete minute structure has in no ease been worked 

 out heretofore, neither has the presence of an integrated system been 

 noted nor its relation to mitosis demonstrated. 



BINARY FISSION 



Binary fission and mitosis in Trichanympha campanula present 

 some interesting pliases, both in regard to cytoplasmic structures and 

 mitotic phenomena, the latter bearing some striking resemblances to 

 certain stages in the mitosis of the metazoan germ cells. These 

 processes will be discussed separately, beginning with the division of 

 the centroblepharoplast and related ectoplasmic structures. 



