OX THE TRYPANOSOME OF THE LITTLE OWL. 
147 
other, the possible significance of which will be discussed 
further. In the early owls Proteosoma occurschiefly in the 
form of schizonts; up to No. 11 inclusive, scarcely any 
gametocytes were found. In the later owls, on the other 
hand, the parasites were mostly in the gametocyte phase, 
schizonts being absent or rare. Halter id ium and Leuco - 
cytozoon, on the contrary, occurred in the g-ametocyte 
phase in the earliest owls in which they were found — Nos. 7 
and 8 ; many individuals were apparently ripe, since they 
“ flagellated,” or became rounded and free, according as they 
were of male or female sex, in the fresh coverslip prepara- 
tions. Indeed, so far as these two intra-cellular parasites are 
concerned, we may take this opportunity of saying that, as 
regards endogenous multiplication or schizogony, we have 
been quite unable up to the present to obtain any evidence of 
such a process, and this in spite of much searching, since 
our return home, of what we considered very promising 
material. 
Owl 23, for instance, had the strongest Halteridial infection 
that either of us has ever observed ; nearly every red blood- 
corpuscle was infected with three or four — sometimes more — 
of these parasites, the majority of them being small forms. 
Whence this host of parasites originated remains a mystery; 
neither smears nor sections of lung and spleen have as yet 
shown anything different from the condition found in the 
general circulation. And the same result lias attended the 
searching of preparations of the organs of earlier birds, 
where the Halteridia were not so abundant in the blood: The 
point remains for future investigation. 
Habitat. 
Turning our attention now more particularly to the try- 
panosomes, it may be remarked in the first place that, so far as 
our observations have gone, the trypanosome of the little owl 
shows a general correspondence with that occurring in the 
chaffinch and redpoll, described in the first memoir. This is 
