1909.) BLOOD-PARASITES OF FRESHWATER WISHES, 25) 
partly to the animal’s movements, partly to deformations induced 
by fixation. Sometimes the anterior end appears pointed and the 
marginal flagellum runs backwards from its point of origin (fig. 36). 
On the other hand, the anterior end may bevery blunt and rounded, 
and the marginal flagellum rons first forwards and then back 
wards from its point of origin (fig. 33). ‘The second type is found 
in an extreme form in preparations dried before fixation (fig. 37), 
and is then undoubtedly largely a case of deformation ; the chief 
mass of the body seems to flow forwards when dried, with the 
result of bringing the kinetonucleus and trophonucle us close 
together. In extreme cases the try panoplasin becomes a shapeless 
mass, in which the orientation of the bocy is difficult to make out 
(figs. 388, 39). It is interesting to note that, Mihi n ycke 
defor med in this way beyond recognition oceur in preparations 
in which the trypanosomes have their body fiir aad structural 
characters preserved quite perfectly. 
The large form of Vrypanoplasma gqurneyorum (fig. 56) also 
has the free flagella velatively short. The bocy el ae is very 
dense and opaque, staining a very deep blue with Gie msa’s stain, 
so that it is very difficult to make out the nucleus; in the speci- 
men drawn in outline in fig. 56 I could see the kinetonucleus 
plainly, especially with green light, but the trophonucleus was 
very difficult to distinguish from the cytoplasm, and I am by no 
means certain that IT have drawn it correctly. 
The most remarkable feature of Trypanoplasma gurneyorwn is 
the presence of deeply staining granules in the cytoplasm, They 
oceur chiefly towards the hinder end of the body, but are found 
also, though more sparingly, up to the anterior extremity. By 
the Romanowsky method (figs. 33-39) they stain deeply in a 
colour approaching the tint of the nuclei, and more especially that 
of the kinetonucleus. By the ivon- hwmatoxylin method they hold 
the stain very fast (figs. 57-65), quite as fast as do the nuclei, a 
point in which they contrast with the eytoplasinic granules of 
Trypanosoma granulosum and 7. perew, he granules are 
especially sharp and clear in preparations fixed with sublimate- 
acetic and stained with iron-hematoxylin (figs. 57-61), They 
are rounded and vary in size from small dots to coarse grains. 
Sometimes there are only a few granules, but as a vule they are 
very numerous and give this trypanoplasm a very characteristic 
appearance, 
Ay ie nuclei of Trypanoplasma quimeyorum appear very different 
according to the stain used, Romanowsky or iron-heimatoxylin. 
The trophonucleus is lodged in ov near the edge of the undulating 
membrane, and hence is difficult to make out clearly if the 
undulating membrane in this part be folded over the body, It 
appears after the Romanowsky stain as a lightly stained patch, 
more or less oval in form, showing no detail or only a few 
ivvegular granulations, After Won -hematoxylin (figs. 57-64) it 
appears as a clear oval space, not very well defined, containing 
