NOTES ON SPOROZOA TV. 
233 
nature of the characteristic spindle-like prolongations iii- 
variabl}' found in connection with the fully grown forms of 
L.ziemanni (and some other species). While I still held 
the view that this parasite (as also Ha 1 teri di u ni) was a Binu- 
cleate and phylogenetically derivable from a Tiypanosome- 
like form (9), I thought it most probable that, at all events 
in the proximal poi'tion of these prolongations, there was some 
ectoplasmic layer belonging to the parasite which helped to 
produce the prolongations. In the case of species whei-e the 
infected leucocytic host-cell remains rounded and does not 
develop any horn-like prolongations (as in L. frij^gilli- 
narum), I regarded the ectoplasmic layer as having been 
completely lost. Howevei’, in my cytological study of L. 
ziemauni, the results of which have been given above, I 
have found nothing to support the presence of any ecto]Dlasmic 
layer. In properly stained individuals (whether stained by 
Giemsa or by iron-haematoxylin) there is no real distinction 
or differentiation to be made out between the most proximal 
region of these prolongations, i. e. nearest to the more 
deeply staining cytoplasm of the parasite, and the distal por- 
tions towards the tip. In the great majority of cases the 
staining (which is always pale) is (piite uniform in tint, only 
becoming gradually fainter as the pi’olongation narrows to its 
extremity (figs. 5-7, 10-12, 18, 22). Very occasionally, in 
Giemsa-stained smears, a space-like area can be seen, 
which is probably more or less artificial. In short, these 
prolongations undoubtedly represent solely the altered 
and extended cytoplasm of the infected leucocyte, this 
characteristic change being caused by the stimulus of the 
invading parasite as it grows. I gather that Wenyon (8) was 
inclined to this view in his account of L. neavei. An 
additional reason in favour of it is supplied by the facts 
in regard to the nuclear structure which I have made 
known, which indicate the essentially Coccidian nature of 
Leucocy tozoon, since the Coccidia lack, of course, any 
differentiated ectoplasmic layer. 
To refer now to certain other points raised by Prowazek, 
