FURTHER OBSERVATIONS ON CLECAL PARASITES OF FOWLS. 69 
metazoan nucleus. On the other hand, we wish to emphasise 
the fact that there is no evidence for regarding the process of 
nuclear division in this form as anything but an arnitosis. It 
would seem that in the later stages of division separation of 
the cytoplasm may proceed more rapidly either at the anterior 
or the posterior pole, and this would explain such appearances 
as are shown in PI. 11, figs. 29 and 30, since here we have 
what we must regard as two late stages of a longitudinal 
division, which, however, are clearly not successive. In PI. 11, 
fig. 29, the in-cutting is proceeding more rapidly at the posterior 
pole, with a result that the two individuals will, at a slightly 
later stage, lie in a head-to-tail position, whereas in PI. 11, 
fig. 30, the in-cutting is proceeding more rapidly from the 
anterior end, and the two new individuals will lie tail to 
tail. 
The last two figures of Trichomonas gallinarum (PI. 
12, figs. 31, 32) are given to show apparent longitudinal 
division resulting in both individuals possessing the relatively 
rare type of nucleus with a distinct karyosome. Whether 
these forms are destined to play some peculiar part in the 
life-cycle of the animal is a question which must remain for 
further work. It is interesting to note that in both these 
cases the forms possess axostyles, which from their position 
can hardly have played the important role in nuclear division 
which has been ascribed to them by some workers. 
It will be evident that Trichomonas gallinarum 
resembles very closely the form described by Prowazek from 
the lizard. 
So far all our attempts at finding any process resembling- 
conjugation have failed. We have found in very large numbers 
a structure which we must regard as identical with the cyst 
described by Prowazek, but the cysts by which we find that 
infection is effected are of a different nature from those 
described by Prowazek. 
To the question of the real nature of this structure we will 
return in a later part of the paper. 
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