UGANDA'S SCOURGE: TRYPANOSOMES 21 



This is thrown into a series of troughs and crests 

 when the trypanosome is moving, and is the chief 

 agent of locomotion. Extending along the edge of 

 the membrane is a stronger band or thread, which 

 stains more brilliantly than the rest of the mem- 

 brane and takes much the same coloration as that of 



FIG. 4 TRYPANOSOMA GAMBIENSE, FROM BLOOD 



b. , Body of parasite ; w. , nucleus (trophic nucleus) ; bl. , blepharoplast 

 (kinetic nucleus) ; m. , undulating membrane ; m.fl. , marginal 

 flagellum ; fl., free flagellum 



the nucleus. This band, which may be termed the 

 chromatic or flagellar border (Fig. 4, m.fl.) of the 

 membrane, extends beyond it for some distance as a 

 free-lashing structure known as the free flagellum 

 (Fig. 4, fl.), also aiding in locomotion. The body of 

 the trypanosome is drawn out at the flagellar end, 

 and it is often difficult to tell where the body proper 

 ends and the flagellum becomes free. The flagellar 



