OCCURRENCE OF NUCLEAR DIMORPHISM IN HALTERIDIUM. 339 
On the Occurrence of Nuclear Dimorphism in a 
Halteridium parasitic in the Chaffinch, and 
the probable connection of this parasite with 
a Trypanosome. 
By 
H. MW. Woodcock, D.Sc.Lond., 
Assistant to the University Professor of Protozoology. 
In the course of an investigation on the Hematozoa of 
birds, undertaken as Mackinnon Student, I have recently 
observed certain forms which are of great importance in 
reference to Schaudinn’s view of the ontogenetic relationship 
between a Trypanosome and a Halteridium of the ‘ Little 
Owl.” 
The material was furnished by a chaffinch, known to be 
infected with a Trypanosome, which was found to be heavily 
infected with Halteridium also, towards the end of last 
June. The preparations of which I shall take account in 
this note were all made between 1 and 3 a.m.; they comprise 
smears from the peripheral blood, the heart-blood, and from 
most of the organs. Unfortunately the lungs were forgotten— 
an omission which I have deeply regretted. The smears 
were all well fixed with osmic vapour and stained by some 
modification of the Romanowsky method. Some of the 
preparations of the peripheral blood were left for a few 
minutes before smearing, with or without the addition of a 
drop of salt-citrate solution. As a result, in these smears 
_ free fully-formed microgametes and free rounded-off female 
elements can be more or less readily found, 
