2 55 
ON THE OCCURRENCE OF SCHIZOGONY 
IN AN AVIAN LEUCOCYTOZOON, 
L. LOVATI, PARASITIC IN THE RED 
GROUSE, LAG OPUS SC OTIC US 
BY 
H. B. FANTHAM, D.Sc. (Lond.), B.A. (Cantab.), A.R.C.S., 
CHRIST’S COLLEGE, CAMBRIDGE, AND LIVERPOOL SCHOOL Oh 
TROPICAL MEDICINE 
(Received for publication 22nd June, 1910) 
Plate XXI 
Although the Parasitic Protoza are much studied at present, there 
is no doubt that more facts are required about the life-cycle of many 
parasites of whose history certain stages are well known. Among 
such parasites are the avian Leucocytozoa. 
During the past two years I have spent some of my time as 
Protozoologist to the Grouse Disease Inquiry, in the investigation of 
the Protozoa parasitic in the grouse. One, at least, of the protozoal 
parasites of the grouse, Eitneria (Coccidium) avium , is the cause of a 
rapid and fatal disease among grouse chicks. Among the parasites 
present in some apparently healthy grouse was a Leucocytozoon, -• 
lovati, first recorded by Seligmann and Sambon in a short note in 
1907. My investigation of L. lovati led to the elucidation of another 
phase (schizogony) in its life history. 
The host cells of the avian Leucocytozoa may be either mononu¬ 
clear leucocytes or erythroblasts, or both. The exact nature of the 
host cell of Leucocytozoa , which is somewhat controversial, will not 
be discussed in this paper. Concerning the Leucocytozoa themselves, 
gametocytes, both male and female, have been described from the 
blood of the host. The male gametocyte of L. lovati (PI. X> , 
%• 0 possesses hyaline, pale-staining cytoplasm, and a rat ici 
large nucleus containing a number of chromatin granu es. 
female gametocyte (fig. 2) has a deeply staining gianulai 
