HiEMATOZOA OF VERTEBRATES. 
85 
Dr. Simond named the species observed by him Hcemamceba 
metchnikovi. While resembling our parasite in general features it 
differs in size, rarely exceeding the half of the blood-corpuscle, in 
the smaller number of its pigment granules, and in the fact that it 
does not cause a displacement of the nucleus of the corpuscle 
according to Dr. Simond’s figures. 
A good demonstration of the difference in size between the two 
species is afforded by the effect of double infection. In the case 
of H. metchnikovi Dr. Simond has figured a corpuscle, otherwise 
normal, containing two parasites, male and female (Simond, Z.6\, pi. 
VIII.,fig. 145). In a doubly infected corpuscle observed by us the 
growth of the two trophozoites had caused a deep constriction of 
the corpuscle, almost cutting it in two (fig. 16). 
It seems clear that Hcemamceba metchnikovi belongs to our 
genus Hcemocystidium , and it should henceforth be styled Hcemo - 
cystidium metchnikovi (Simond). The name Hcemocystidium 
will probably be found of use as a distinctive term, but until all 
the stages of the life-history of the parasite are known it can only 
be regarded as a provisional designation. 
H^mogregarinidjs. 
Hcemogregarina nicorice,n . sp. 
The species of the genus Hcemogregarina are often difficult to 
distinguish from each other and the principal and most obvious 
means of differentiating them is by host and locality. Our 
brief account of the above-named parasite will add little to the 
knowledge of the hasmogregarines beyond indicating a new 
distribution. 
The larger specimens of the tortoise commonly met with in 
ditches and marshy lands round Colombo and in the Colombo lake, 
Nicoria trijuga , appear generally to be infected with a non- 
pathogenic haemogregarine which does not betray any highly 
distinctive properties. 
When examined in the fresh condition the crescent-shaped or 
reniform body of the parasite presents one clear pole, one granular 
pole, and a clear but sharply defined central tract which in stained 
preparations proves to contain the nucleus. More frequently than 
not the clear pole is directed towards the nucleus of the blood- 
corpuscle, but there is no constant orientation. 
The granular pole is the growing end of the organism which 
becomes bent round upon itself in the manner characteristic of 
the genus Hcemogregarina . The doubling of the parasite usually 
takes place by a very narrow bend, but occasionally a wide bight is 
produced (fig. 19). Young stages before the bending came 
