306 KOFOID AND SWEZY. 



far from the chromatic basal rod in his figure 119, 1, 2, and 4, is quite 

 possible under the conditions of preparation of smears. Brumpt's 

 interpretation of his excellent figures, as well as our own, requires 

 further in\estigation before either can l)e finally accepted for these 

 species. 



In all species in which this chromatic basal rod is present it lies 

 along the base of the undulating membrane. In certain imperfectly 

 known species such as Trichomonas hominis Donne, T. 'vaginalis 

 (Davaine), T. limacis Dujardin, T. suis Grube and Delafond, T. 

 tritotds Alexeieff, and T. parva Alexeieff, it has not been adequately 

 described, if at all. From its uniform presence in all species of tricho- 

 monads having an undulating membrane which have been adequately 

 investigated, it seems probable that it will be found to be co-extensive 

 with that structure in this group of flagellates. Further light on its, 

 homologies is suggested by the fact that it lies in the same undulating 

 membrane with the intracytoplasmic part of the posterior flagellum, 

 originates from the same blepharoplast with it, runs in the same direc- 

 tion, and differs from it only in its deeper location, larger caliber, and 

 in the fact that it does not project beyond the cytoplasm. In function 

 also it differs in the absences of undulating waves of contraction. 

 There is thus much to favor the view that this chromatic basal rod 

 might also be regarded as an intracytoplasmic flagellum parallel to 

 the marginal flagellum. 



However, the fact that it has no motor function militates against 

 this view. It belongs rather to the series of intracytoplasmic chroma- 

 tic structures in the Trichonymphida elaborated near the blepharo- 

 plast and nucleus and connected with the former by a fiber. Janicki 

 (1911) called these structures the parabasal bodies. Homologous 

 structures were found by x\lexeiefl' (1911a) in Heteromita lacertae 

 and called by him "batonnets siderophiles " and also in Monocerco- 

 monas bufonis where the name "corps siderophile" was used to 

 designate them. There is a strong probability that the so-called 

 kinetonucleus of the Trypanosomidae and related forms belongs in 

 this same series, provided we recognize as distinct from the kineto- 

 nucleus the blepharoplast at the base of the flagellum adjacent to the 

 kinetonucleus. 



The dift'erences in form between chromatic basal rot!, corjjs sidero- 

 phile, parabasal body, and Idnetonucleus are correlated to some 

 extent at least with other structural differences. The well-developed 

 undulating membrane in Trichomonas is correlated with an elongated 

 parabasal at its base. In the absence of such a localized motor area 



