ON THE TRYPANOSOME OF THE LITTLE OWL. 
153 
this, there was strikingly little difference to be noticed among 
the numerous parasites observed. We certainly never saw 
anything resembling the curious appearances and behaviour 
of the parasites described by Dutton, Todd and Tobey (3) in 
another species of Leucocytozoon; and in this respect our 
observations concur with those of Wenyon (17). 
Many individuals were watched very carefully for signs of 
movement, but in no instance did we see any active move- 
ment or change of form, either of the ovoid, more internal 
(endoplasmic) part of the parasite or of the tapering extremi- 
ties of the spindle. The latter, probably consisting at any 
rate in the narrower portions only of the cytoplasm of the 
host-cell, were sometimes seen to bend slightly to and fro, 
quite passively, this motion being caused, doubtless, by little 
currents in the blood-plasma in the immediate neighbour- 
hood. We never observed any amoeboid movement or any- 
thing comparable to the waves of constriction described by 
Wenyon in the case of L. neavei ; neither did Mathis and 
Leger (8 and 10) in their form from the fowl. Of course, in 
referring to this absence of movement in the parasites, we 
are not taking into account the preliminary efforts of ripe 
gametocytes either to rupture the host-cell or to form micro- 
gametes. It is possible that the observations made by 
W enyon may refer to such ripe gametocytes which were 
endeavouring to free themselves from the leucocytes ; though 
it is true we always found this process to occur very rapidly 
in L. ziemanni. The reason why we have laid stress on 
the entire absence of active movement in the ordinary spindle- 
shaped individuals — which was always the case in every bird 
in which we studied them — is to emphasise the fact that we 
never saw any indication whatever of the development of 
locomotor organellas, or of any active trypan i form phase. 
Further, we have never once found, either in living prepara- 
tions or in the permanent smears, any young or intermediate- 
sized individuals or forms other than the ripe gametocytes, 
free in the blood-plasma, however numerous the parasites 
were . 
