NOTES ON SPOEOZOA LV. 
225 
latter was tbeu known), when both were stained by a reliable 
cytological method, I was at the time quite justified in 
reufardinor the nuclear condition in Halteridium as coi- 
responding closely to the karyosomatic type of nucleus seen, 
for instance, in a Tiypanosome ; and, further, in considering 
the definite, small associated element to represent a kineto- 
nucleus in a “ riickgebildet ” condition as Berliner suggested. 
As a matter of fact, even until quite recently, and since I have 
realised the essential Coccidian nature of tlie nucleus of 
Leucocy tozoon, I have been at a loss to explain this 
apparent resemblance of the Hal te rid i u m-nucleus to the 
binucleate condition and its difference from that of Leuco- 
cytozoon. 
It is only within the last few weeks that I have learnt the 
true explanation of the matter and at last definitely settled, 
as I consider, the meaning of the nuclear appearance seen in 
Halteridium. The mistake has really been, 1 believe, in 
comparing the small associated granule, seen in films stained 
by irou-hoematoxylin, with the conspicuous, deeply staining 
organella seen in Giernsa-stained smears, at any rate so far 
as I’egards the adult parasites. It so happens that some of 
my best iron-luEinatoxylin preparations of H. noctuEe are 
from an owl which had a heavy iiifection, and in which the 
great majority of the parasites were young, or intermediate- 
sized forms, relatively few being full-grown individuals. 
Looking over these at the time tliey were made, and again 
before writing the postscript above alluded to, I remember 
noting the general uniformity which was apparently [iresented 
by the nuclear structure. The small forms, the intermediate- 
sized ones and the few large parasites I came across all showed 
the karyosomatic type of nucleus, with or without the small 
accessory granule (and this is to be regarded, of course, as 
the regular condition, cf . figs. 24-27). As I then remarked, 
what I observed corresponded closely with what Berliner 
had figured. This being so, I did not undertake any 
systematic searching of these preparations at that time, as 
I wanted to continue first my study of the Avian Trypano- 
VOL. 58, PART 1. NEW SERIES. 15 
