N. H. SwELLENGREBEL AND C. STRICKLAND 
367 
Diagram, IV. 
Fjgs. i— 3 , Different stages of the wandering of the nucleus and the blepharoplast. G. 
Third day. The crithidiae are now abundant in the midgut, also 
some pre-crithidial stages are yet to be found (Diagram V, Fig. 2). 
Diagram, V. 
Figs. 1—2. Transformation of a trypanosome into a crithidia. G. 
Figs. 3—4. Slender crithidiae. G. 
Figs. 5, 6 , 9. Stout crithidiae (formation of large oval forms). G. 
Fig. 7. Stout crithidia ; blepharoplast between the two nuclei. G. 
Fig. 8 . Stout crithidia, flagellum unstained, blepharoplast and nucleus close together. G. 
Figs. 10—12. Large oval forms, Figs. 10 and 11, G, Fig. 12, I. H. 
Figs. 13—16. Large oval forms being transformed into round forms. G. 
Fig. 17. Round form. G. 
Fig. 18. Pseudo copulation. G. 
Among the crithidiae two types may be distinguished: 
(a) Club-shaped forms (Figs. 1, 6, and 9) often with a more or less 
reduced flagellum (Figs. 5, 7, and 8). 
(b) Slender crithidiae with a well-developed flagellum (Figs. 3 
and 4). 
Both types are connected by intermediate forms. One might be 
tempted to consider this differentiation as a sexual one, but we never 
