N. H. SwELLENGREBEL AND C. STRICKLAND 
371 
two chromatic granules at both ends. In Fig. 2 the blepharoplast is 
divided and one of the nuclei shows undoubted signs of a renewed 
division, being elongated and more or less constricted in the middle. 
The subsequent stages of nuclear division will be described below. 
A general peculiarity of the round forms is the occurrence of darkly 
staining granules scattered in the protoplasm. A flagellum may be 
present or absent, and if absent there may be no sign of any basal 
granule. 
Eighth day and afterwards. Whereas the developmental stages of 
the previous days showed a more or less marked progression in relation 
to each other, this is no longer the case with the stages of the eighth 
and subsequent days. Although a great variety of forms are produced, 
there is no further progression to be observed and the forms found 
during these days are all the same, therefore we describe and figure 
them together. 
In the unstained gut many oval inactive and active flagellates and 
round forms are adherent to the pyloric region and to the rectum. 
Beside these small active flagellates with a well-marked undulating 
membrane active oval forms and free round forms are to be seen 
in hindgut and rectum. There is no well-marked difference between 
the contents of hindgut and rectum ; all the different types may be 
Diagram X. I. H. 
Fig. 1. Rosette of round forms. 
Fig. 2. Rosette of small oval forms. 
Fig. 3. Round form with dividing nucleus. 
Fig. 4. Small round form. 
Figs. 5—12. Transformation of small oval forms into crithidiae. 
Fig. 13. Large crithidia. 
Figs. 14—15. Small trypanosomes. 
Fig. 16. Rosette composed of small oval forms, crithidiae and intermediate forms. 
