N. H. Swellengrebel and C. Strickland 
383 
These large oval forms are generally united into rosettes (Diagram 
XVII, Fig. 1) with round forms, which confirms our view that the two 
are connected. 
Diagram XVII. Different forms of rosettes. G. 
Moreover, rosettes are found in which round forms and small 
crithidiae (identical with the small oval forms of the flea’s gut) are 
present (Figs. 2 and 3), so we may conclude that these small oval 
forms are produced by the division of the round forms. 
Apart from these forms, larger crithidiae with the nucleus and the 
blepharoplast in the front end of the cell (Diagram XVIII, Figs. 1,2, 3) 
are frequently to be found; we do not know if they are to be ranged in 
Diagram XVIII. Different forms of crithidiae and leptomonads. G. 
the series before the large oval or after the small oval forms. Small 
crithidiae (or perhaps better herpetomonads) are also to be seen 
(Fig. 4) which may perhaps arise from the small oval forms. 
The flagellates found in the louse taken from the rat three days 
after it lost its trypanosomes, show different changes which we think 
must be interpreted as degenerative. Large, dark-staining granules 
appear in the cells (Diagram XIX, Fig. 2), the nucleus stains very 
