20 PROF, E. A. MINCHIN ON PROTOZOAN [Jan. 12 
side to side in even curves like a snake. They frequently stop 
suddenly, and wriggle actively in one place like an excited earth- 
worm, and then start off again in a new direction. J never saw 
them ‘travel with the flagellum directed backwards. The un- 
dulating membrane is very distinctly seen, and shows beautiful 
rippling movements. Progression appears to me to be effected 
chiefly by twists and turns of the body, aided doubtless by the 
undulating membrane ; the flagellum has perhaps chiefly a tactile 
or euiding function. ‘The kinetonucleus is very distinct in the 
ivi condition as a refringent granule a short way from the 
hinder end. The trophonucleus is more difficult to see during 
life. 
Although my preparations were made only with the object of 
adding to my collection, they show some points of interest, which 
I will state briefly. 
In the first place my preparations show trypanosomes of all 
sizes from very small to very large (figs. 1-7). The contrast 
between the two extremes of the series is surprisingly great, but 
all possible transitions from one extreme to the other are to be 
met with. Nor can I find any definite structural features to 
separate sharply the large and small forms, as can often be done 
in trypanosomes of other species. The large forms are very 
granular, while in the smallest granules are absent or scarce, but 
this feature shows both variations and transitions; the large 
forms have more pleats in the undulating membrane than the 
smaller, but the pleats are about the same depth and simply 
increase in number with the length of the trypanosome. The 
free flagellum bears about the same proportion, as regards length, 
to the rest of the body in both large and small fo'ms, though im 
some large forms it is perhaps relatively shorter. The differences 
in the nucleus, to which I shall refer presently, are also differences 
due to a gradually increasing complexity of structure. I cannot 
therefore find characters to separate sharply the varieties magna 
and parva of Lebailly. 
A very marked feature of this species, when stained by the 
Romanowsky method, is the occurrence of numerous granules in 
the cytoplasm, a peculiarity to which it owes its name. The 
granules stain purple or blue with Giemsa’s stain. In prepara- 
tions stained with iron- -hematoxylin, the granules are only to be 
seen when the stain is not sufficiently extracted (fig. 83); when 
the stain is most satisfactory and the flagellum and nuclei are 
sharp and distinct, the characteristic granulations are not to be 
seen. One of my coverslip-smears is rather uneven and thicker 
in some parts than in others. In the thicker portions the stain 
is less extracted than in the thinner parts of the smear, as 
commonly happens, and hence different degrees of extraction can 
be found in the preparation. Only a very few trypanosomes show 
the granules stained and standing out sharply; with too slight 
extraction of the stain the granulations are obscured by the 
darkness of the cytoplasm. If the stain 1s very much over- 
