NOTES ON SPOROZOA IV. 
227 
the species of Halteridium infecting them are distinctly 
lai-ger, it will be noticed, in tlie case of the little owl than in 
the case of the chaffinch. Hence the cytological details can 
be made ont with somewhat less difficnlty in the gametocytes 
of H. noctuEe, though of course not nearly so readily as in 
Leucocy tozoou . It happened very fortunately that in 
■one of my infected owls, the Halteridial parasites possessed, 
for some reason or other, very little pigment; many of my 
figures are drawn from this series of preparations, because in 
such a case there is no possibility of confusing the nuclear 
elements with pigment grains.' As is apparent from the 
figures, the nuclear structure agrees closely with that of 
L. ziema nni, and thei’efore a detailed description is unneces- 
sai-y. As regards the large, oval, pale nuclear area in the male 
forms, I have never observed any indication of the peripheral 
zone of deeply staining chromatic grains, which are often so 
prominent iii L. ziemanui; whether this is because they 
are not developed in the male nucleus of Halteridium, or 
merely because 1 have not succeeded in getting them to 
stain, I cannot say. There is, however, the same small, 
spherical, peripherally situated karyosomatic body, which 
now and again can be distinctly seen to be surrounded by a 
clear halo (fig. 30) ; and, close to it, the same dumb-bell 
shaped or else double centrosomic element. ^ 
'I’lirning now to the female gametocytes, it was the obser- 
vation of the large, adidt parasite (H. fringillae) drawn in 
fig. 32 which suggested to me the explanation of the 
difference generally to be seen between the female nucleus 
of Halteridium and that of Leu coc y tozoon. In the 
' It is perhaps scarcely necessary to say that this rather unusual 
feature does not imply that the nuclear details themselves differ at all 
from the condition found in other cases, whei'e the parasites have the 
usual siqiply of pigment grains ; the nuclear structure is obviously 
(juite similar in my figures of H. fringilliB, which show numerous 
grains. 
’ In the case of Halteridium, these granules are so minute that 
it is difidcult to believe they can be anything but the actual centrioles 
themselves. 
