218 11. M. WOODCOCK. 



phis, although owing to the intensity with which thekineto- 

 nucleus stains lie is unable to be certain. Prowazek frequently 

 figures such a centrosomic granule, situated between the 

 kinetonucleus and the base of the flagellum, in both T. lewisi 

 and T. brucii. Sometimes this granule is closely attached 

 to the kinetonucleus, and appears separated by a short gap 

 from the flagellum; at other times it is attached to the 

 flagellum and separated from the kinetonucleus. As the 

 author points out, it is probably homologous with that at the 

 base of the flagellum in other cases, and, indeed, as already 

 stated, Prowazek finds the minute structure and development 

 of this region entirely comparable to that described by 

 Schaudinn in Trypanomorpha and Trypanosoma 



ziemanni 



Bearing this in mind, it seems most likely that there is, as 

 a rule, actual organic union between the flagelhim and the 

 kinetonucleus, even where there appears to be a gap between 

 the two. Probably the delicate connecting-thread (or axial 

 spindle of an earlier division, see above, p. 185) is not easily 

 demonstrated.^ In the majority of Trypanosomes the flagellum 

 is described as joined to, and originating from, the kineto- 

 nucleus (figs. 16, 17). Even in those cases where there is a 

 clear zone around the latter, and the flagellum seems to begin 

 at the outer border of the halo, Laveran and Mesnil consider 

 that there is, nevertheless, an unbroken union between the 

 two organellas ; for, in involution forms of the particular 

 Trypanosome concerned, when most of the organism has 

 perished, kinetonucleus and flagellum still persist, intimately 

 united. 



• An interesting point bearing on the view that the ilagelhun represents 

 the greatly elongated axial spindle of a nuclear division may be noted. In 

 Trypanosoma johnstoni, where there is no free portion of the llagelluui, 

 this terminates (at the limit of the cytoplasm) in a small deop-slaining 

 granule, which is perhaps comparable to the distal centrosome of tlie axial 

 spindle (compare also pp. 197-8). 



^ In one or two maceration preparations of T. brucii, Prowazek was able 

 to see this connecting fibril. 



