Figure legend

FIGURE 12. A trophozoite of P. lophurae. The nucleus reveals spindle fibers (Sf) and a few pair of minute, elongated electron dense structures (arrows). They are in the axis of the spindle fibers, at right angles to the fibers and midway between the poles, and may be chromosomes. X 40000.

Figure notes

A process of schizogony begins early in the growth of the trophozoites. Nuclear division appears to initiate this process before any other significant cytoplasmic changes take place. One of the most noticeable changes during the nuclear division is the appearance of spindle fibers within the nucleus (Figs. 11-13). The spindle fibers are composed of several micro tubules, measuring 200-220 A in diameter and running from one nuclear pole to the other. In the nuclear division the nuclear membrane is preserved except around the region closely associated with the poles of spindle fibers (Fig. 11).