﻿102 Proceedi7igs of the Royal Physical Society. 



and the paler red substance forms a set of fine (Figs. 43a and 

 44) fibres which may connect the two daughter structures for 

 some time. This band of fibres can sometimes be traced 

 after it has broken in the centre, and may every now and 

 then produce rather confusing appearances. It ultimately 

 disappears in the protoplasm. I am inclined to think that 

 the paler substance which, as it were, bathes the darker 

 chromatic elements, becomes fibrillar, and effects division in 

 much the same way that the central fibres do in the case of 

 the trophonucleus. In the blepharoplast, of course, the 

 process seems to approach nearer to amitosis. 



Slight variations occur both in the division of the tropho- 

 nucleus and the kinetonucleus, but they are not sufi&ciently 

 important to be gone into here. The division of the two 

 nuclear elements in all stages is fairly independent of each 

 other. 



The nuclear division of the other forms assumed by this 

 parasite is peculiarly difficult to obtain in complete series, 

 although specimens with two nuclei are relatively quite 

 common. The chief variation, as far as I can see, is that in 

 most of the trypanosome forms the division figure disappears 

 much more rapidly, and while the nuclei are still often quite 

 close to each other. 



I am ignorant as to how division occurs in the slender 

 trypanosome, with the chromatin arranged in bars as in 

 Figs. 25-27. 



The appearances presented by the various forms during 

 the later stages of division, after the mitosis of the tropho- 

 and kinetonucleus, are of considerable interest, especially as 

 they frequently simulate conjugation. I propose, therefore, 

 to describe the more striking cases. 



To begin with the early Herpetomonas forms, the division 

 of the preflagellar bodies and their relation to the kineto- 

 nuclei has already been described. As regards the division 

 of the protoplasm, the greatest possible variation is to be 

 found. 



Thus division may occur from the non-blepharoplast end (i.e., 

 the posterior end of the Herpetomonas stage), as in Fig. 48, 

 or from the blepharoplast end (Fig. 36). The two creatures 



