172 
H. WOODCOCK. 
work at the time to undertake a study of this parasite, so 
that I only made a few smears and cover-slip preparations 
from the blood. 
Having an opportunity recently, I thought it might prove 
worth while to give some nttention to these preparations, 
particularly to those stained by iron-hpematoxylin, because — so 
far as I am aware — no observations have been made up to the 
present upon the nuclear structure of Karyolysus, as it is 
seen when the parasite is fixed and stained by the best cyto- 
logical methods. My idea was, principally, to compare the 
nucleus of this Haemogregarine with that of the piscine form 
(Hasmogregarina rovignensis) from Tri gla 1 i n eata, 
an account of which has been given by Minchin and Wood- 
cock (20). I had not long examined my preparations, 
however, before observing that a remarkable agreement was 
apparent between the nuclear condition of Karyolysus at a 
certain period of the life-cycle and that of a particular 
Coccidian in the corresponding phase. A study of the different 
forms of individual present in my smears has led me to the 
conclusion that they all belong to one species of parasite, 
d’his result has an important bearing, in my opinion, upon the 
question of the distinctness of many of the so-called species 
of Lacertilian Haemogregarine which have been described, as 
I hope to show below. Lastly, the observation of the occur- 
rence of a prominent karyosome, whose behaviour agrees 
closely with that of the characteristic coccidian karyosome, 
induced me to study again, from this point of view, the 
nuclear condition present in Leucocy tozoon and Halteri- 
dium, as it is found in these parasites when fixed and stained 
in a similar manner. 
II. Observations on Karyolysus lacert.® (Danil.), 
TOGETHER WITH KeMARKS UPON THE SPECIFICITY OF THE 
Ha'Imogregarines of Lizards. 
1 will first give an account of Karyolysus as it occurs in 
my preparations. With two or three exceptions, all the 
