STUDIES ON CEYLON H#MATOZOA. 669 
or myonemeta can be seen running longitudinally along the 
body; these are sometimes extraordinarily clear, and are 
especially conspicuous just before the animal rounds itself off. 
The flagellum runs forward from the kinetonucleuas—which 
can occasionally be distinguished in the live specimen—along 
the edge of the undulating membrane and ends in a long free 
whip. The waves of contraction which pass along it make 
little sharp corners appear at what may be called the bays of 
the frills, giving a very characteristic appearance, though one 
difficult to describe in words. 
Bright inclusions may be present all along the body, 
arranged without any appearance of regularity; they are 
often entirely absent, and I never discovered upon what 
either their absence or their presence depended. ‘The body 
of the Trypanosome is apparently oval in section. The poste- 
rior end extends some way beyond the kinetonucleus; it is 
changeable in shape, and may be drawn out to a rapidly 
tapering point, or be rounded off and rather blunt. 
‘he movements of this Trypanosome are rather complicated, 
and it can execute a considerable number of different figures. 
Like many Trypanosomes its motion of translation in the 
blood of the vertebrate host is relatively speaking slight ; 
this is in marked contrast to the extraordinarily rapid darting 
movements of certain of the forms developed in the trans- 
mitting host. Quite possibly this lesser power of actual 
translation through space is correlated with the fact that the 
parasite in the vertebrate blood is in a medium which is 
itself in motion. Trypanosoma vittatz shows the wheel 
motion so often seen in Trypanosomes in fishes; it also 
executes repeated serpentine twisting, sometimes in a figure 
8, or even following a simple U-curve down one limb and up 
the other. The most characteristic movement, however, is a 
rather slow, forward spiral twisting. The Trypanosome will 
sometimes go on revolving slowly round its long axis with the 
body in the shape of a corkscrew, and with hardly any for- 
ward motion at all. The spiral twisting often occurs rhyth- 
mically forwards and backwards, through a distance of about 
