HiEMATOZOA OP VERTEBRATES. 
83 
distribution of the genera, # three families may be recognized :— 
Hsemamoebidse, comprising the malarial parasites of man, apes, 
bats, and birds ; Piroplasmidse, comprising the parasites causing 
Cattle fevers (Texas fever, Rhodesia fever, &c.) ; lastly, the 
Hsemogregarinidse, including a large assemblage of endoglobular 
parasites of fishes, amphibia, and reptiles. 
We now pass on to summarize our own observations on these 
organisms. 
H^mamcebid^e. 
Halteridium danilewskyi (Grassi and Feletti). 
This parasite has been described from many birds in different 
countries. All are regarded as belonging to the same species. 
The blood of a common Scops Owl ( Scops bakkamcena var. 
malabaricus) taken recently (July) in Colombo proved to be 
abundantly affected by it. Only endoglobular phases were with 
certainty observed by us, and these showed the sexual differentia¬ 
tion of the trophozoitesf already noted by MacAllum. In our 
preparations there are two kinds of fully developed trophozoites, 
present in approximately equal numbers, perhaps rather more of 
the first kind than of the second. In one form the protoplasm 
is stained distinctly blue with Leishman’s mixture, leaving a 
clear tract in the centre, pigment granules being scattered more or 
less throughout the protoplasm. These, according to MacAllum 
(as quoted by Minchin), are characters of the female parasite. 
The second type shows characters of the male. It has generally 
a shorter and stouter form, appearing nearly white, very faintly 
bluish white, owing to greater density of the protoplasm, and the 
pigment-granules are aggregated at the two ends. In one instance 
we observed a double infection of a blood-corpuscle by the two 
forms (fig. 7). There are indications that the granular or female 
parasite undergoes amoeboid movements. Young oval stages of 
the trophozoite are also present though not common. 
The conversion of the male trophozoite into a gametocyte can 
be followed in our stained preparations. The parasite becomes 
shorter, thicker, and finally nearly round (fig. 9). 
* Cf. Minchin, E. A., Sporozoa, in A Treatise of Zoology, edited by Professor E. 
Ray Lankester, Part I., Fascicle 2, 1903, p. 265. 
•j* The terminology employed here is based upon that laid down by Professor 
Minchin in the treatise to which we have already referred. The parasite grows 
in the blood-corpuscle from a minute germ to its full size. During this stage of 
endoglobular growth the parasite is called a trophozoite. When a trophozoite 
becomes sexually mature it is called a gametocyte. MacAllum’s original papers 
published in the Journal of Experimental Medicine, vol. III., 1898, have not been 
accessible to Us, 
