NEW TYPE OF PEOTISTAN PAEASETF. 
449 
We have uot found such well-marked indications of division 
in ovals possessing a large area of dark-staining material as 
in those of the other type ; but we are inclined to think that 
the same transverse binary fission occurs. A not uncommon 
feature in ovals of this type is the presence of two definite, 
intensely staining granules, one at the middle of each of the 
longer sides of the body (figs. 67, 69-71). Frequently these 
two granules are connected by a fine line, which is sometimes 
seen to follow the external contour of the body (fig. 70), when 
it probably represents a very slight annular constriction 
across it ; but at other times the line can be traced with diflii- 
culty through the body (fig. 69). It seems probable that 
these appearances indicate transverse division, but we do not 
think it occurs to nearly the same extent in ovals showing 
this second condition of the internal structure. 
We may now consider briefly the question of the connection 
of these different types of form with each other, and of their 
association together as different phases of one parasite. In 
the first place, ovals showing the second type of minute 
structure can be readily connected with those showing the 
first condition described, by a series of intermediate stages. 
All degrees in the thinning out of the darker staining area 
until it is little more than a narrow peripheral ring (as in 
fig. 59) can be found ; and from such a stage to that shown 
by the individuals, for instance, of figs. 39 or 40 is a very 
slight transition. Another marked transition stage is seen in 
fig. 42, where the narrow peripheral, intensely staining zone 
is slightly thickened around one end ; such a condition is 
manifestly closely connected with that showing a cap of 
dark-staining substance at each end (as in figs. 60, 61). It is 
a little difficult to know what interpretation to assign to this 
darker-staining part of the protoplasm, as found in the 
second type of oval. In the ovals with a well-marked, finely 
granular peripheral layer, or with more conspicuous granules, 
we consider that this zone comprises the chromatinic material 
of the cell, just as in the case of the crescents. Are we, then, 
to regard the more or less homogeneous, darker staining 
VOL. 59, PART 3. NEW SERIES. 29 
