OCCURRENCE OF NUCLEAR DIMORPHISM IN HALTERIDIUM. 343 
In none of the male forms scrutinised so far have I been 
able to make out a distinct kinetonuclear body. This may 
be because it is not differentiated, as a compact organella, 
from the rest of the diffuse nucleus of this type. (I am 
inclined to think, however, that it is present in the free, fully- 
formed male gametes, although it is difficult to feel quite sure ; 
I shall refer again to the structure of these delicate elements.) 
Moreover, in many of the female individuals, the kineto- 
nuclear element is by no means so prominent or separate as 
in the examples figured, which have been chosen to show this 
feature as clearly as I have observed it. Others, again, do 
not show it at all. It is quite probable that at times the two 
TEXT-FIG, 7. 
Free form, from heart-blood; smear made at once. xX 2500. 
(Probably the upper nuclear body is the kinetonucleus.) 
constituents are incorporated in one nucleus, as was said, 
indeed, by Schandinn to occur at certain periods. 
It is highly significant, I think, that up to the present, 
when an intra-cellular parasite has been known to exhibit 
nuclear dimorphism, although lacking in that stage any 
flagellum or obvious sign of Flagellate affinity, it has been sub- 
sequently found to be really a phase in the life-cycle of some 
Flagellate form; in other words, the knowledge of nuclear 
dimorphism in a parasite has hitherto heralded, as it were, 
the discovery of its intimate connection with a Flagellate. 
The classic instance is the Leishman-Donovan body, whose 
flagellar phase was first made known by Rogers. Again, 
Schaudinn himself maintained that certain Piroplasmata 
showed this character, and others (e.g. Lihe) have since 
corroborated him. Only recently Miyajima! has carried the 
1 «Philippine Journ. Sci.,’ ser. B, vol 2, p. 85, 1907. 
VOL. 53, PART 2.—NEW SERIES. 24 
