i 9 9 
tertian zygotes, three and a half days old (12 x 12/1), in its 
mid-gut; the pigment was in the form of linear rods, and almost 
every zygote had a zonal arrangement of its pigment. The zone of 
pigment was made up of rods, end to end, each rod separated by 
a small space; sometimes the zonal pigment was concentric with the 
periphery of the zygote, sometimes at right-angles to the plane 
presented to the observer, but apparently always peripheral. 
In Experiment No. 33, a specimen of Ce. albimana contained 
twelve to fifteen malignant tertian zygotes, three and three-quarter 
to four and three-quarter days old, 12 x 13*5 n in size, mostly 
oval in outline. The pigment was bronze in colour, and in clumps, 
never in lines or belts. In experiment No. 36 a specimen of 
Ce. albimana contained malignant tertian zygotes five days old, 
21 fi in diameter, with the pigment present in clumps. On 
counting the number of pigment rods in a zygote, and in crescents, 
it is evident that conjugation of gametes does not occur, for there 
is the same amount of pigment in each instance. In Experiment 
No. 42, a specimen of Ce. albimana contained several malignant 
tertian zygotes of three ages (three bitings from the same patient). 
Five or six zygotes were between one and a half and two and a half 
days old, and their pigment, of course, tightly clumped. One 
zygote, 21 n in diameter, was globular and contained three 
clumps of pigment, while in several others of the same age the 
zygotes were oviform and the rods of pigment were arranged in 
pairs, scattered irregularly throughout the zygote, each one 
containing thirteen or fourteen rods of pigment. 
In most of the zygotes, excepting the very young or very old 
forms, the pigment was arranged in lines or belts, but not 
uncommonly zygotes were seen of equal age in the same specimen, 
some with belts of pigment, and some having it in clumps. 
1 he larger zygotes, containing sporoblasts, showed very little 
pigment. This is collected in one clump, usually near the 
periphery. The pigment is probably not destroyed nor extruded, 
but is partly obscured by the greater size of the zygote. 
Some of the smallest zygotes contained dancing pigment, and 
>n the larger zygote, with zones of linear pigment, the zone could be 
seen to change its position very slowly, but in these instances the 
pignient was not dancing. 
N 
