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H. M. WOODCOCK. 



in the middle. The trophonucleus increases in size, and its chromatin 

 becomes arranged in eight rather elongated chromosomes, which next begin 

 to divide in a similar dumb-bell-like manner (fig. 24 c). The trophonuclear 

 karyosome (karyocentrosome) has frequently divided by this time (c) ; but 

 in one case Prowazek observed it much drawn out and functioning as an 

 intranuclear division centre (d), the chromatin having become aggregated 

 around its two ends. In fig. 24 c the chromatoid grains in the cytoplasm 

 are also seen dividing. 



The division of the general cytoplasm takes place last of 

 all. In the great majority of forms this is equal or sub-equal 

 and the two resulting daughter-Trypanosomesare of approxi- 

 mately equal size (figs. 23, 25 c). Although the cytoplasmic 

 fission usually begins at the flagellar end, it is important to 



Fig. 24. — Nuclear details in the division of T. brucii. A — B, 

 division of the kinetonucleus; c and D, of the trophonucleus. 

 (After Prowazek.) 



note that it may commence instead at the non-flagellate ex- 

 tremity. This is the case (according to both Lignieres and 

 Elmassian and Migone) in T. equinum, where the division 

 starts indifferently at either end (cf. fig. 25 c and d). It 

 would be very interesting to know at which extremity it 

 begins in Trypanoplasma, but, unfortunately, only an 

 early stage has, up till now, been described for this form 

 (fig. 26), and many more details are needed. 



In .some instances (e. g. T. brucii, T. equinum [fig. 25 k], 

 T. equiperdum [fig. 25 o]) the longitudinal fission is appar- 

 ently multiple, the original individual giving rise, simultane- 



